Materials from the Teach Computing Curriculum created by the National Centre for Computing Education

A user of this program said, “I have used selection but when I enter the wrong answer, nothing happens.” Why did nothing happen?

Which program will have an outcome every time key 'p' is pressed?

The program below is not working when key 'space' is pressed. Why not?

Testing a Quiz

﻿Hello and welcome to selection in quizzes. My name is Josh, I'm your computing teacher. And in lesson six, we're going to look at evaluating the quizzes that we created in lesson five. You're going to look at how you can make improvements, and how you can ensure that your quiz is user-friendly, for everybody that wants to use it. You will need access to the Scratch website, so make sure you have that. You will also need your project from lesson five. So make sure you are either loading it from your computer, if you downloaded it, or taking it from your account, if you have an account. Remember if you're under the age of 13, and you would like an account, you will need your parent, carer or teacher, to help you set that up. You don't need an account, so don't worry if you don't have one or don't want one. You will need something to write on and with, so make sure you have that to hand. And if you've got all of those bits ready, let's crack on with the last lesson of our unit. So, in this lesson you're going to evaluate your programme. To do that you're going to identify ways the programme could be improved, you're going to identify what setup code you need in your project, and you're going to extend your programme further. Before we do any of that, we're just going to have a quick recap, on selection and conditions. So I would like you to just have a look at programme A and B. I'd like to pause the video, and I'd like you to consider whether the same selection and conditions, have been used in both programmes. Pause the video, have a quick think, resume the video when you're done. Okay, so hopefully you have checked out whether or not the selection and the conditions are used the same, in both programmes. And hopefully you have identified that they are not, okay. The conditions are different. It's only the conditions, the rest of the programme is the same, the conditions are different. So one of the conditions is answer equals yes, and one of the conditions is answer equals no. So hopefully you spotted that. And that was just a really quick recap on selection and condition. Let's move on to evaluating our programmes then. So three different users tried my quiz. They all knew the correct answers, but only one got all of the questions in my quiz right. Three users all knew the correct answers, but only one got all of the questions right. Let's have a think about why. So these are the user inputs that were given, user A, B and C. User A says I put the answers yes, no, yes, I got all of the questions right. User B, I put the answers yep, no and yes, I only got two questions right. And user C said I put the answers true, false and true, and I got all of the questions wrong. We'll need to pause the video, read through the user inputs again, and have a think about why, only one of the users got all of the questions right. Okay, so hopefully you've noticed that that the reason only one of these has got all questions right, is because of the inputs they gave. So user A used yes, no and yes, and they got all of the questions right. That means that our user inputs, should be yes, no and yes. User B has used no and yes for the second two questions, but for the first one, although they knew the answer, they used the word yep. And in user C's case, he used true and false, instead of yes and no. My condition in my programme, was yes, no and yes. So answer equals yes, answer equals no, and answer equals yes. So although user B and user C, both knew all of the answers, they didn't use the correct words, in order to answer that question. And that is based on my programme, where I specified the words yes and no, should be used as the conditions. Let's have a quick look at this code snippet. I'd like you to identify what input a user needs to give, to answer the question correctly. What input would a user need to give, to answer the question correctly? Pause the video, have a quick look at the code snippet and a quick think, resume the video when you're done. Okay, so hopefully you've noticed that the user would need to give the input, correct. That is the condition, answer equals correct. So in order to answer the question correctly, they need to use the word correct, when responding to the question. And that is a really important factor, isn't it? It's really important that the user uses the correct words, in order to answer our questions in our quizzes, because that is how the quiz has been programmed. So want you to have a quick think about how could you make the user, aware of how to answer the questions in your quiz? And that's an improvement that we need to look at. And that brings me on to task one. What I'd like you to do, is I'd like you to have a think about how you could improve your project, to make it more user-friendly. You just had an idea given to you, that's one thing that you could think about. But how else could you improve your project as well? Make some notes, pause the video, and resume the video when you've done that. Okay, welcome back. Hopefully, you have made some notes down on how you could improve your project, and things that you could do to make it better. I'm really hoping that you also made a note about, the user inputs and how you can make sure users are aware, of the correct way of answering your questions. Let's have a quick look at how I've changed my project, so you can see. Okay, so I had a think about how I could make sure that users are using the correct phrases, in order to answer my questions. And the way I've decided to do this, is to let the users know exactly which words to use, to answer them. So what I've got at the top here, is a say block, that says, please use yes or no to answer the questions. And I'm just going to pop that, in between these two blocks here, so it says, welcome to my capital city quiz. Then it says this little say block here, which tells them how to answer the question. I'm actually going to change that to four seconds, just to give people a little bit longer to read it, and then it goes into my questions. So now, it should ask say welcome to my quiz, then say please use yes or no to answer the questions. And then it asks the first question. So that's just one way we could look at making sure users know, which words to use to answer the questions. And it's a really simple way, of ensuring that people are using the correct phrases. Now, this might not work if your answers are not yes or no. You might have, as before I had, what is the capital of Spain, they have to give the actual word. But that's a little bit more straightforward, than if the answers are yes or no, or true or false, or correct or incorrect. So that's just one way that we could use, to ensure that users know how to answer the questions in our quizzes. So you've made some notes on how you can improve your quiz, to ensure that users are able to answer the questions correctly, and hopefully you've made some notes on other things that you could do to improve your quiz as well. One of those things is about setup, and setting up our programme. So every single user, that uses your quiz should have the same experience. Why don't you just have a think and consider whether or not, your question, the outcomes, or the sprite's starting appearance, change once your quiz has been played once. Okay, so we're going to have a quick look at mine, and just see what happens, when my quiz is played through once, and then the next person can use it. And we'll see if the starting position of my sprite, needs to be amended. So let's run through my quiz first, and see how we get on. So remember when to use yes or no to answer the questions, as it says there. Is Madrid the capital of Spain? Yes. Okay, is Reykjavik the capital of Iceland? No. Oh, good try. Is Berlin the capital of France? Yes. Okay, and is Rome the capital of Italy? No. Okay, thank you for playing my quiz. I hope you enjoyed it. Excellent. So, I've played it through once, you can see my sprite has changed colour, he's slightly changed his position, and he slightly changed the way he is facing. So instead of facing 90, he's now facing 105. If I play the quiz again, although the colour changes back, it hasn't reset my sprite to the middle of my page, and it hasn't changed the rotation. You can see that down here. So now if I run it through again, and say, is Madrid the capital of Spain? And I say no, I made it a little bit smaller. Is Reykjavik, I'm going to say no. You can see it has changed my position of my sprite costume again. Is Berlin the capital of France? Of course is, oh, no it's not. And is Rome the capital of Italy? Yes. It's played my meow sound. And you can see that if I play again, although it will change the colour back, it does this automatically, it won't change anything else. So the user experience each time is different. And that's one thing that we need to think about changing, so that everyone has the same experience. So as you've just seen, my programme doesn't start the same way each time, even though it should do. Okay, remember we want the users to have the same experience every single time they play our quiz. To do this, we need to tell the computer how the sprite should appear, at the start of our quiz. And this is called the setup. And it's very much like setting up, or preparing a board game each time you try and play it. So if you're playing monopoly for example, you would make sure that all of the starting pieces, are on the go part of the board, and you've got your chance cards, okay, in their space. Every person's got the same amount of money. It's all setup at the start. So we need to do something similar, for our quizzes. While as you stare I'd like to pause video, I'd like to think about what these command blocks on your screen do. So pause the video, have a think about what each of the four command blocks do. Okay, welcome back. So hopefully you've had a think then about what each of these command blocks do. The first one, go to x and y. Okay, that tells us where our sprite should be on our screen. It's the coordinates on our screen, of where our sprite should be. And 00 is the centre of our screen. So if we said go to 00, is going to put us right back in the centre of our screen. Pointing in the direction of 90, remember it's looking at angles, and it's pointing to the right. Okay so, it's pointing in that direction. So if you've got rotation, in your project, in your programme, then you need to make sure that you are returning that sprite back to facing 90, which is the way it should face and it faces when you start your programme. Next one is set size to 100% if you've got anything in your programme, where it increases the size or reduces the size, and you need to think about returning the sprite back to it's 100% size, which is again the size that it starts off. And finally, although we we saw in that last one, that setting colour effect to zero, won't really have an effect because it automatically changes in colour back, it's still good practise to include it in our setup. And that will reset the the sprite's colour back to its original colour. So in the case of the Scratch cat, it returns it back to that orange colour that he is originally. Remember, even if you only have one of your outcomes has moved across the screen, for example, you still need to make sure you include it in your setup, just in case somebody has that experience. So even if one of them moves it across the screen, hey, and it's no question, as unlikely that somebody would get that question wrong, you still need to keep it in there and put that in the setup, just in case somebody does use that question. Okay, so your next task is to make a note of the setup blocks you will need. Okay so, on your worksheet you have a number of the setup blocks, just like we had just there. You might need some more setup blocks, so have check through Scratch and see if there's anything else you might need to add, to ensure that your programme, returns to the start as it should do. Pause the video, have a go at making a note of the start setup blocks that you'll need, and resume the video when you're done. Okay, welcome back. Hopefully you've made a note of the blocks you will need, in order to create your setup part of your programme. And this remember is taking it back, to where it should start. So every user, it starts in the same position each time, okay. And you could do that by adding it after, your flag, your green flag pressed, and it will, once you press that return the sprite back, to its original position. We're going to look at extending our programmes now, okay. So what I'd like you to go and do, is I'd like you to implement any of the changes that you have identified. Once you've implemented those changes, it's really important that we continue to run and test our programmes, just to ensure that the user's experience will be improved. So your final task, is to use the blocks that we identified earlier, to setup your programme, and improve your programme, and make it the same experience for every user. So pause the video, go and do that now, and return to the video once you've finished. Okay, welcome back. Hopefully you've gone away then, and you have improved your programmes. You've extended them, you've added in blocks that will help with the setup, and you've made the whole experience, a lot better for your users. Let's go away and just have a quick look at mine, and just see how mine works. So here is my programme. As you can see I've split my programme just so it's easier to see where my setup is, and we're just going to through this together. So I've added in a few of blocks. So I've added a go to x 00, that's my starting position. I've added point in direction of 90, which is the way I wanted to originally point. Switch costume to costume one, and that's because in this part here, you can see I've added a next costume in there. So if they get the answer wrong on this question, it will change to the next costume. So I want him to go back to its original costume. Okay, and I've added in set colour of vector zero. Remember, although it does this automatically, it's a good idea to have that in there just as a process that you know how to do. And then set size to 100%, which is the original starting size. So what you can do, in order to test that your setup works the way you want it to work, you can separate it first, you can play around with the size, the position, and the direction. So I'm going to say I want him to be 50, I put him at 180, and the sprite Scratch's sprite is currently at 144, y minus 66. I've split it, so it's not going to ask me any questions, but it is going to show me if my setup is correct. That's the first thing I want to do. So I'm going to press the green flag, and you can see he returns to 00, his size goes back to 100, he points in the direction of 90 which is facing right, and he is bright, the costume, is the original sprite costume. So what that's done has is allowed me to see that my setup works the way I want it to work. And now that I've tried that, remember I've got my please use yes or no, I've extended my programme already by using that. Now if I run through my programme, and I'll do that very quickly, you'll be able to see that the start of each time, so each time the green flag is pressed, he will change position. Okay, so that's the end of my quiz. If I press the green flag again, you can see it resets my sprite, back to the position I would like him to start in. So every user will have the same experience going through my quiz, and from where they start, to where it finishes. So that was my improved programme. And we're just going to go back to the task that we had. And the task was to create an interactive quiz, using selection. Now that was mostly based around your lesson four design, and your lesson five testing, okay. Because you should have already had that selection based quiz, ready to improve for this lesson. And I'm hoping, that you will feel like you have met that task. Now, we added more to it, afterwards. We added in our say block, to ensure that people knew how to answer the question, and we added in setup code to ensure that our users had the same experience each time. So we're going to now very briefly look at evaluating our quiz even further, right. So what I'd like you to do, is I'd like you to pause the video, and I'd like you to consider these questions. Okay, did you meet the requirements of the task? Did you create an interactive quiz that used selection? Okay, which parts of your programme worked well? And which parts are you happy with? Which parts of your programme did you improve? Okay, so remember that we had to test and if it didn't work, we went back and improved it, and then we added more improvements as went go through. And finally, what further improvements might you make? So I'd like you to pause the video, and consider those questions, and resume the video when you finish. Okay, so hopefully you've had a think about those four points, and you've identified whether you've met the requirements of the task, I'm hoping you have. You've identified parts that worked well, and I hope you found some of those because it's always nice to point out the things that you're happy with, you're proud of. I hope you've identified things that you had to improve, and you've done that as you went through. And now finally, we can think about further improvements. Okay, so we've added our setup code, we've added our say block, to ensure that people know how to answer the question. What else could you do to improve your project? For me, personally, I might go back and change my project to make it a little less boring. At the moment it's just a plain white background, with the Scratch cat, as my sprite. A few questions, and they're done. Okay, so it works well, and it would met the requirements of the task, but it's not as engaging as I would like it to be. So I might go back and change my background, I might consider where my backgrounds might change, the change based on the selection choice, or would it change based on the question? Okay, there are lots of ways you can improve it, you might want to change your sprite, so it's a different sprite. You might want to move your sprite to different places on the screen, before each question, based on what's on the background. Lots of things you can do. And I really recommend pausing the video, going away and tinkering with your project, making it better, improving it further, making it more engaging. There's lots of ways you can do that, and I really do recommend doing that. Please remember to save your project to your computer, if you don't have a Scratch account, so you don't lose anything you've created. Okay, and then you can use that in the future, you can share it with others, and just really get that feedback on your quiz, so that you can continue to improve it. That is the end of lesson six, our final lesson for the unit of selection and quizzes. I hope you've enjoyed it, I've really enjoyed teaching it. And I hope you've made something that you're proud of, and that you're happy to share with others, to gather that feedback and improve it further, and just really be proud of what you've created. If you'd like to share with us here at Oak National Academy, we would love to see it. So please consider doing that. You can ask your parent or carer, to share it on Instagram, Facebook or Twitter, tag @OakNational and #LearnwithOak. Once again, I've really enjoyed this unit, I hope you have too. Please continue tinkering with your programmes and your projects, and playing around in Scratch. It's a really fun thing to do. Okay, it's really exciting to be able to create things that you can share with others. I hope you've had a great time with this unit. I look forward to seeing you again soon.

Every time I run the program, my sprite will face to the right. True or false?

Which blocks could you use for program setup?

Which programs contain an example of selection?

Evaluating a Quiz

In this lesson, we will return to our completed programs and identify ways to improve them. We will focus on issues where answers similar to those in the condition are given as the input and identify ways to avoid these issues. We will consider how to ensure all uses are provided with the same experience and identify if we have met the requirements of the given task.

Lesson overview:Evaluating a quiz

Core Content

Selection in Quizzes: