A magazine is considering the launch of an online edition Th

A magazine is considering the launch of an online edition. The magazine plans to go ahead only if it is convinced that more than 25% of current readers would subscribe. The magazine contacts a simple random sample of 500 current subscribers, and 137 of those surveyed expressed interest. Should the company launch the online edition? Use alpha = 0.05. A medical study finds that in a random sample of 27 members of a treatment group, the sample mean systolic blood pressure was 114.9 with a sample standard deviation of 9.3. Is this enough evidence to conclude that the mean systolic blood pressure of the population of people taking this treatment is less than 120? Use alpha = 0.1. In UNL, usually more than 2000 students are enrolled in an introductory statistic course each year. A student wonders how much he should pay for a textbook for this course. Consequently, he randomly selected 40 students who were enrolled last year and recorded how much each person paid for the textbook. Below are the recorded amounts. Conduct a test at a 5% significance level on whether students paid on average different from the manufacturer\'s retail price of $64 for the textbook during the past year.

Solution

4) H0: P=0.25

H1: P>025

Z=p-P/sqrt(PQ/n)

n=500

p=137/500

P=0.25

since p value is 0.1076>0.05, we accept the null hypothesis So the comapny should not go ahead with the campaign.

5) H0: mu=120

H1: mu<120

t=xbar-mu/s/sqrt(n-1)

xbar=114.9

n=27

mu=120

s=9.3

p is<0.05, hence we reject the null hypothesis.

6) xabr=sum(fx/40)=61

mu=64

n=40

s=7.8421 this is sample standard deviation of the sample.

z=xbar-mu/s/sqrt(n)

p<0.05, hence H0 is rejected.

Hypothesis test for proportion vs hypothesized value
	Observed	Hypothesized
	0.274	0.25	p (as decimal)
	137/500	125/500	p (as fraction)
	137.	125.	X
	500	500	n
		0.0194	std. error
		1.24	z
		.1076	p-value (one-tailed, upper)