1. A random sample of 49 California college students found that the amount of mo

Question

1. A random sample of 49 California college students found that the amount of money they spent annually on textbooks had a mean of $898 with a standard deviation of $265.

(a) Make a 98% confidence interval for the mean annual textbook cost of all California college students interpret in interval.

(b) At the 5% significance level, can we show that the mean annual textbook cost of all California college students is less than $1,000? State and test appropriate hypotheses. State conclusions.

(c) Find the p-value of the test (b).

Explanation / Answer

a)Z for 98% confidence level is 2.33

Hence, the interval is[ 898- 265*2.33/sqrt(49), 898+265*2.33/sqrt(49)]=[809.79, 986.21]

b) Z = (x-mean)/[sigma/sqrt(n)] = (1000-898)/[265/sqrt(49)]= 2.694

P-value for z = 2.694 is 0.9965

Hence, we can say that the mean is less than 1000

Related Questions

Navigate

• Browse (All)
• Browse 1
• Subjects

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.