The mean life of a battery used in a digital clock is 305 days. The lives of the batteries follow thenormal distribution. The battery was recently modified to last longer. A sample of 20 of themodified batteries had a mean life of 311 days with a standard deviation of 12 days. Did themodification increase the mean life of the battery?(a) State the null hypothesis and the alternate hypothesis.(b) Perform a hypothesis test and state your decision and conclusion at a = 0.05

The question is about hypo. testing Given : Popl. mean life of a battery ( μ ) = 305 days Sample no.…

Answered: The mean life of a battery used in a…

MATLAB: An Introduction with Applications

6th Edition

ISBN:9781119256830

Author:Amos Gilat

Publisher:Amos Gilat

Chapter1: Starting With Matlab

Section: Chapter Questions

Problem 1P

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A sample of 10 from population 1 has a mean of 32 and a standard deviation of 6. A sample of 13 from population 2 has a mean of 48 and a standard deviation of 8. The population standard deviations are unknown but assumed to be equal. Test the hypothesis, at the 1% level of significance, that the population means are the same. State your conclusion as a sentence and include the test statistic and the critical value.
The mean height of a certain kind of plant is 170 centimeters. Suppose we want to carry out a hypothesis test to see if the mean height when these plants are treated with a certain chemical differs from 170. State the null hypothesis H0 and the alternative hypothesis H1 that we would use for this test.
You are conducting a study to see if the proportion of women over 40 who regularly have mammograms is significantly less than 0.24. Thus you are performing a left-tailed test. Your sample data produce the test statistic z=−2.665z=-2.665. Find the p-value accurate to 4 decimal places.
The next six questions refer to the following scenario: A random sample of 25 students were asked to self-identify as "statistics-lovers" or "statistics-adorers." 16 students self-identified as "lovers" and 9 students as "adorers." Below table summarizes the mean of a statistics test and standard deviation that was given after the self-identification. Test the following hypothesis at alpha=5% (0.05). HO: Mean Statistics Lovers = Mean Statistics Adorers HA: Mean Statistics Lovers Mean Statistics Adorers You can assume equal variance.
You are conducting a study to see if the accuracy rate for fingerprint identification is significantly different from 0.51. Thus you are performing a two-tailed test. Your sample data produce the test statistic - 2.153. Find the p-value accurate to Z = - 4 decimal places. p-value
A psychologist is studying smokers self images, which she measures by the self image (SI) score from a personality inventory. For adults in the U.S., the mean SI score from this inventory is about 140. The psychologist gathers a random sample of 17 SI scores of smokers and finds that their mean is 164 and their standard deviation is 38. Assume that the population of SI scores of smokers is normally distributed with mean μ. Based on the sample, can the psychologist conclude that μ is different from 140? Use the 0.05 level of significance. Perform a two-tailed test. Then complete the parts below. Carry your intermediate computations to three or more decimal places and round your answers as specified in the table.
A simple random sample of 95 basketball players is taken from different teams and their mean weight is found to be 226 pounds and the standard deviation of the population is 20 pounds. Using 0.05 level of significance, test the claim that the average weight for all basketball players is 231 pounds. Complete the following steps: Step # 1: Write the null hypothesis Ho [ Select ] and the alternative hypothesis H1 [ Select ] and identify the claim [Select] Step # 2: Indicate what type of test has to be used [Select ] and find the critical value(s). ( Select ] Step # 3: Find the test value. [ Select ] Step # 4: Make the decision about the null hypothesis. [ Select ] Step # 5: Summarize the result. (Select J
You believe that your morning commute to UCLA is decreasing every week. You record thetime of 7 commutes (one for each day of the week) (in minutes) for the a one-week block and thenthe following one-week block. * Calculations have been done for you: the sample mean difference is -1.714 and the sample standarddeviation is 2.984. Conduct a hypothesis test at the α = 0.15 level. The mean difference calculated as the the first one-week block minus the second one-week block. That is to say week one minus week two. a. Set up the null and alternative hypothesis (using mathematical notation/numbers and interpretthem in context of the problem) b. Calculate the test statistic for the test from part a
A sample is selected from a population with = 150. After a treatment is administered to the individuals, the sample mean is found to be = 140 and the standard deviation is S= 9. If the sample has n = 18 scores, determine whether the sample is sufficient to conclude that the treatment has significant effect. Use a two tail test with = 0.02.
You are conducting a study to see if the proportion of women over 40 who regularly have mammograms is significantly less than 0.66. Thus you are performing a left-tailed test. Your sample data produce the test statistic z=−1.812z=-1.812. Find the p-value accurate to 4 decimal places.
You are conducting a study to see if the accuracy rate for fingerprint identification is significantly less than 0.24. Thus you are performing a left-tailed test. Your sample data produce the test statistic z=−2.287z=-2.287. Find the p-value accurate to 4 decimal places.p-value =
Researchers wish to investigate whether anxiety in children has increased over time. In 1950, the average score on the Child Manifest Anxiety Scale was µ= 15.1. A sample of n = 16 was taken from children today, which produced a mean anxiety score of M= 23.3 with SS= 240. Based on the sample, has there been a significant change in the average level of childhood anxiety since 1950? (Use a 2-tailed test with α= .05) Write a sentence describing the outcome of the hypothesis test as it would appear in a research report.

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