What is the mean number of hours that high school students spend on homework per week? it is known that the standard deviation of the population is 2.2 hours. in a random sample of 40 students, it is found that they average 13 hours per week on homework.

a) what is the standard deviation for this sample?
b) what is the critical value for a 90% confidence interval?
c) what is the critical value for a 95% confidence interval?

p ÷ r = tan(x)

step-by-step explanation:

given that there is a figure below shows a right triangle: a right triangle is shown with hypotenuse equal to q units and the length of the legs equal to p units and r units.

graph is missing so i will create the graph as per given information.

the angle between the legs having lengths p units and q units is y degrees. the angle between the legs having lengths r units and q units is x degrees.

now we need to find about what is p ÷ r equal to.

so we can use trigonometric ratio tan(x)=[altitude]/[base] to find the value of p ÷ r, because p is the altitude and r is the base.

p ÷ r=tan(x)

hence final answer is p ÷ r=tan(x).