00:03
In this question, we want to estimate the average difference in the percentage of foreign revenue for tech companies and basic consumer product companies.
00:16
After you've verified the mean and standard deviations for the two types of companies, we can plug these numbers into our confidence interval formula.
00:26
And notice here i'll answer question d.
00:28
I'm using t -star, the t -distribution, because this is quantitative.
00:33
Data and we do not know the population standard deviations.
00:38
All we know are the sample standard deviations.
00:41
Now i've plugged in my means, my standard deviations, and my sample sizes, but my t -star, our smallest sample size is 16, which means our degrees of freedom is going to be 15, and we want an 85 % confidence interval for degrees of freedom 15.
01:02
And our t -star for that is 1 .517...