00:01
So our question says that a group of statistics students decides to conduct a survey at the university to find the average amount of times students and studying per week.
00:10
Assuming a population standard division of 13 hours, what does the require sample size if the error should be less than half an hour with a 95 % confidence interval level rather? so that means our population standard deviation is equals to 13 hours.
00:26
Our margin of error is actually cost less than half of an hour there is 0 .5 hours.
00:34
Our confidence level is 95 percent, so we need the value of the sample size.
00:40
The formula for the margin of error m .e is actually giving us the critical value times the population standard division divided by the sprouting of n.
00:49
So our critical value is going to be based on a zscore, and that is because we know the value of the population standard division.
00:56
And we are going to assume that our data set is normally distributed.
01:00
At a confidence level of 95 % our alpha level is equals to 5%.
01:07
So that means our critical value is going to be, let's use a calculator.
01:12
So we have this to be standard normal 2 tiled and this is definitely going to be 0 .05...