00:01
Hello, so i'm going to answer your question about proportions and a specific application in calculators for doing so first i answer your question about the issue about how to calculate the confluence interval for a proportion when you have a 99 % level, so this is this formula what you need to is take the proportion of the issue and then add -tum subtract the error so in your case you have that for an alpha of 99 % or a confidence interval of 99 % you want to calculate this proportion, specifically the upper value.
00:36
So what you need to do is take the proportion of the issue, then the cita associated to the alpha level, in your case is 2 .58, and then p, that is 5 over 950 times 1 minus p, that 1 in this case i regretted 950 minus the proportion of the calculators that have a defect over the total sample size, 950, then i resolve this square root, the result will be this one, then i multiply it by the cet associated to that alpha level that gives me 0 .01, and the upper value will be 0 .026.
01:13
And this will tell you that with 99 % of confidence, you can say that the maximum amount of calculators that had an effect will be 2 .6%.
01:25
Now the second question is to calculate the sample size that with a 95 % confidence interval will give an error of 2%.
01:35
So what i did is just take this part that is the error.
01:38
Then i apply i use so you want to have a maximum 2%...