Question

A) What is the probability that a randomly selected student purchased exactly 3 textbooks in the previous semester? Enter as a decimal

B) The distribution of study time for students at a particular university is normally distributed with a mean of 1.2 hours and a standard deviation of 0.25 hours. Administration is worried that some students are spending too much time studying. They want to reach out to those students in the top 4% of study times. They will reach out to students who study more than how many hours? Round to the nearest hundredth.

Answer 1

Given that,

mean = = 1.2

standard deviation = =0.25

Using standard normal table,

P(Z > z) = 4%

= 1 - P(Z < z) = 0.04

= P(Z < z ) = 1 - 0.04

= P(Z < z ) = 0.96

= P(Z <1.75 ) = 0.96

z = 1.75 (using standard normal (Z) table )

Using z-score formula  

x = z * +

x=1.75 *0.25+1.2

x= 1.6375

x=1.64