Suppose you carry out a significance test of H0:μ=5versus H0:μ>5based on a sample of size n =20 and obtain t = 1.81.

(a) Find the P-value for this test using (i) Table B and (ii) your calculator. What conclusion would you draw at the 5% significance level? At the 1% significance level?

(b) Redo part (a) using an alternative hypothesis ofH0:μ5

Short Answer

Expert verified

a. The p-value is0.0431

b. the p value is 0.086

Step by step solution

01

Introduction

A p-value estimates the probability of obtaining the noticed outcomes, it is consistent with expectations that the invalid hypothesis. The lower the p-esteem, the more prominent the statistical significance of the noticed difference

02

Explanation Part (a)

the sample size n = 20

t= 1.81

the hypotheses are,

H0:μ=5Ha:μ>5

calculating the degree of freedom we have,

df=n1=20-1=19

The p-value is,

=P(t>|t|)=P(t>|1.81|)=0.0431

The p-value is greater than the significance level α=0.01and less than the significance level α=0.05

The null hypothesis is rejected and hence the evidence is not sufficient.
03

Explanation Part (b)

the sample size n = 20

t= 1.81

the null and alternative hypotheses are,

H0:μ=5Ha:μ5

The degree of freedom is 19

calculating the p value for two tailed test,

=2×P(t>|t|)

=2×P(t>|1.81|)=2×0.0431=0.086

Since the p-value is greater than the significance levels the null hypothesis is not rejected.

Hence there is sufficient evidence.

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Most popular questions from this chapter

A government report says that the average amount of money spent per U.S. household per week on food is about \(158. A random sample of 50households in a small city is selected, and their weekly spending on food is recorded. The Minitab output below shows the results of requesting a confidence interval for the population mean M. An examination of the data reveals no outliers.

(a) Explain why the Normal condition is met in this case.

(b) Can you conclude that the mean weekly spending on food in this city differs from the national figure of\)158? Give appropriate evidence to support your answer.

Bottles of a popular cola are supposed to contain 300milliliters (ml) of cola. There is some variation from bottle to bottle because the filling machinery is not perfectly precise. From experience, the distribution of the contents is approximately Normal. An inspector measures the contents of six randomly selected bottles from a single day’s production. The results are 299.4297.7301.0298.9300.2297.0Do these data provide convincing evidence that the mean amount of cola in all the bottles filled that day differs from the target value of 300ml? Carry out an appropriate test to support your answer

(a) State hypotheses for a significance test to determine whether first responders are arriving within 8 minutes of the call more often. Be sure to define the parameter of interest.

(b) Describe a Type I error and a Type II error in this setting and explain the consequences of each.

(c) Which is more serious in this setting: a Type I error or a Type II error? Justify your answer.

(d) If you sustain a life-threatening injury due to a vehicle accident, you want to receive medical treatment as quickly as possible. Which of the two significance tests—H0:μ=6.7versusHa:μ<6.7 or the one from part (a) of this exercise—would you be

more interested in? Justify your answer.

A random sample of 100likely voters in a small city produced 59voters in favor of Candidate A. The observed value of the test statistic for testing the null hypothesis H0:p=0.5versus the alternative hypothesis Ha:p=0.5is

(a)z=0.59-0.50.59(0.41)100

(b). z=0.59-0.50.5(0.5)100

(c). z=0.5-0.590.59(0.41)100

(d). z=0.5-0.590.5(0.5)100

(e).t=0.59-0.50.5(0.5)100

A researcher claims to have found a drug that causes people to grow taller. The coach of the basketball team at Brandon University has expressed interest but demands evidence. Over 1000 Brandon students volunteer to participate in an experiment to test this new drug. Fifty of the volunteers are randomly selected, their heights are measured, and they are given the drug. Two weeks later, their heights are measured again. The power of the test to detect an average increase in height of one inch could be increased by

(a) using only volunteers from the basketball team in the experiment.

(b) using A=0.01 instead of A=0.05.

(c) using A=0.05 instead of A=0.01.

(d) giving the drug to 25 randomly selected students instead of 50.

(e) using a two-sided test instead of a one-sided test.

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