Assume that you have a sample of n,8, with the sample mean X, 42, and a sample standard deviation of S, 4, and you have an independent sample of n₂-15 from another population with asample mean of X₂=34 and a sample standard deviation of S₂-5. What assumptions about the two populations are necessary in order to perform the pooled-variance t test for the hypothesisH:1P2 against the alternative H₁: pp and make a statistical decision?Choose the correct answer belowA. It is necessary to assume that the populations from which you are sampling have independent normal distributions and equal variances.B. It is necessary to assume that the populations from which you are sampling have equal population means and positive standard deviations.OC. It is necessary to assume that the populations from which you are sampling have negative ISTAT fest statistics and unequal sample means.OD. It is necessary to assume that the populations from which you are sampling have unequal variances and equal sizes.

The t-distribution is very useful probability distribution when the sample size is small and the…

Answered: Assume that you have a sample of n,8,…

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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Suppose a sample size of 87 was used to conduct a right tailed hypothesis test for a single population mean. The null |hypothesis was Ho: µ 45 and the sample mean was 50 and the p-value was 0.03. Then there is a 3% chance that 87 randomly selected individuals from a population with a mean of 45 and the same standard deviation would have a sample mean greater than 50. false true
C and D only
4) We are running a hypothesis test to see if weight of African zebras is significantly different than that of Arabian horses. We assume weight in both populations is normally distributed and both populations have the same population variance in weight which is unknown to us, so we use the sample variances to estimate the standard error for our calculations. Our sampling has 8 African zebras and 6 Arabian horses. We find 3.01 as the absolute value of our standardized test statistic for our sample data. Is this data significant at the .02 level of significance? NONE OF THE OTHERS NO YES
The breaking strengths of cables produced by a certain company are approximately normally distributed. The company announced that the mean breaking strength is 2140 pounds with a variance of 32,761. A consumer protection agency claims that the actual variance is higher. Suppose that the consumer agency wants to carry out a hypothesis test to see if its claim can be supported. State the null hypothesis Ho and the alternative hypothesis H₁ they would use for this test. Ho: H₁: 0 μ OSO 0=0 X X Р ☐#0 S O0 020
We are running a hypothesis test to see if weight of African zebras differs significantly from that of Arabian horses. We assume weight in both populations is normally distributed and both populations have the same population variance in weight which is unknown to us, so we use the sample variances to estimate the standard error for our calculations. We have a sample size of 9 for the African zebras with mean 650 and a sample of size 16 for the Arabian horses with mean 658. If the pooled variance is 36, then what is the value of the standardized test statisitic for our data?
The records of a casualty insurance company show that, in the past, its clients have had a mean of 1.7 auto accidents per day with a variance of 0.0025. The actuaries of the company claim that the variance of the number of accidents per day is no longer equal to 0.0025. Suppose that we want to carry out a hypothesis test to see if there is support for the actuaries' claim. State the null hypothesis H and the alternative hypothesis H, that we would use for this test. H0:__H 1:__
To evaluate the effect of a treatment, a sample is obtained from a population with a mean of =40, and the treatment is administered to the individuals in the sample. After treatment, the sample mean is found to be M = 44.5 with a variance of s² = 36. If the sample consists of n = 16 individuals, are the data sufficient to conclude that the treatment has a significant effect using a two-tailed test with a = .05? O For these data, t= 1.50. This value is less than the critical value of 2.131, so we reject the null hypothesis and conclude that there is a significant treatment effect. O For these data, t = 3.00. This value is greater than the critical value of 2.131, so we reject the null hypothesis and conclude that there is a significant treatment effect. O For these data, t = 4.50. This value is greater than the critical value of 2.131, so we reject the null hypothesis and conclude that there is a significant treatment effect. O For these data, t = 1.50. This value is less than the…
A researcher decides to measure anxiety in group of bullies and a group of bystanders using a 23-item, 3 point anxiety scale. Assume scores on the anxiety scales are normally distributed and the variance among the group of bullies and bystanders are the same. A group of 30 bullies scores an average of 21.5 with a sample standard deviation of 10 on the anxiety scale. A group of 27 bystanders scored an average of 25.8 with a sample standard deviation of 8 on the anxiety scale. You do not have any presupposed assumptions whether bullies or bystanders will be more anxious so you formulate the null and alternative hypothesis based on that.
2. Scored obtained by a large group of students taking a test are known to be normally distributed. A random sample of twenty-five students test scores yielded the following statistics: 25 と=1Xi 25 1508 x - 95628 Find a 95% confidence interval for the population mean.
An independent consumer group published its finding that the lifetimes of electric bulbs manufactured by BIG Corporation are approximately normally distributed with a mean of 660 days and a variance of 15,625. BIG Corporation claims that the variance of its electric bulbs is less than 15,625. Suppose that we want to carry out a hypothesis test to see if BIG Corporation's claim is correct. State the null hypothesis H0 and the alternative hypothesis H1 that we would use for this test. H0: H1:

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