A group of statistics students decided to conduct a survey at their university t

Question

A group of statistics students decided to conduct a survey at their university to find the average (mean) amount of time students spend studying per week. Based on a simple random sample, they surveyed 144 students. The statistics showed that the student population studied an average of 20 hours per week with a standard deviation of 10 hours.
(a) What is the standard error of the mean?

(b) What is the probability that a sample mean would exceed 20 hours per week?

(c) What is the probability of finding a sample mean less than 18 hours?

(d) What is the probability that average student study time is between 18 and 22 hours?

Explanation / Answer

a. Standard error of the mean= standard deviation/sqrt(n)= 10/ sqrt(144)= 10/12= 0.83 b. 50% c. z = 18-20/ 10= -2/10= 0.2. Look up z table= 7.93 %. So, the probability Pr(X

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