For Problems 3–11, please provide the following information.
- (a) What is the level of significance? State the null and alternate hypotheses.
- (b) Find the value of the chi-square statistic for the sample. What are the degrees of freedom? What assumptions are you making about the original distribution?
- (c) Find or estimate the P-value of the sample test statistic.
- (d) Based on your answers in parts (a) to (c), will you reject or fail to reject the null hypothesis of independence?
- (e) Interpret your conclusion in the context of the application.
- (f) Find the requested confidence interval for the population variance or population standard deviation. Interpret the results in the context of the application.
In each of the following problems, assume a
Sociology: Marriage The following problem is based on information from an article by N. Keyfitz in the American Journal of Sociology (Vol. 53, pp. 470–480). Let x 5 age in years of a rural Quebec woman at the time of her first marriage. In the year 1941, the population variance of x was approximately σ2 = 5.1. Suppose a recent study of age at first marriage for a random sample of 41 women in rural Quebec gave a sample variance s2 = 3.3. Use a 5% level of significance to test the claim that the current variance is less than 5.1. Find a 90% confidence interval for the population variance.
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Chapter 10 Solutions
Understandable Statistics: Concepts and Methods
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- For the following pairs of assertions, indicate which do not comply with our rules for setting up hypotheses and why (the subscripts 1 and 2 differentiate between quantities for two different populations or samples):arrow_forwardIf your question is that your significant hypothesis test is significant “enough” to have true meaning, what are some other things you can look at to determine practical significance?arrow_forwardFor problem 1, perform the hypothesis test. 1) Bob grows pumpkins. He claims that the average weight of his pumpkins is greater than 5.6 lbs. Test his claim if a simple random sample was collected when: the mean of the x scores = 5.9, standard deviation = .3 lb, and the sample size = 81.arrow_forward
- Need answers for these questions . Using the Chi-square statistical tablearrow_forwardFor each of the following situations, state whether you would use a chi-square goodness-of-fit test, a chi-square test of homogeneity, a chi-square test of independence, or some other statistical test. Complete parts a) through c) below. a) Is the quality of a car affected by what day it was built? A car manufacturer examines a random sample of the warranty claims filed over the past two years to test whether defects are randomly distributed across days of the work week. Choose the correct answer below. A. Chi-square test of independence. You have data on two variables, day and quality, for one manufacturer. B. Chi-square goodness-of-fit test. You want to see if the distribution of defects is uniform over the variable day. C. Chi-square test of homogeneity. You have two samples and one variable, day. You want to see if the distribution of quality is the same in the two years. D. Some other statistical test. The variable day is…arrow_forwardWe want to compare cholesterol levels between men and women, so we collect a sample of 20 women and 30 men. The group of men in our sample have a mean of 240.0 with standard deviation 35.0, and the women have a mean of 210.0 with standard deviation 30.0. What is the null hypothesis? Note that two-sample problems (like this one) were not discussed in class, but you should know the answer (or at least be able to provide a good guess below) based on what was covered in class. Group of answer choices The mean cholesterol level in men is equal to the mean cholesterol level in women The mean cholesterol level in men is different than the mean cholesterol level in women The mean cholesterol level in men is less than the mean cholesterol level in women The mean cholesterol level in men is less than the mean cholesterol level in womenarrow_forward
- In the picture there is a given data and based from that data. There is no significant difference between the perceived level of riskiness of thrill behavior in males and in females. (Use a= 0.05) Identify the Null hypothesis and Alternative Hypothesisarrow_forwardA manufacturer of chocolate chips would like to know whether its bag filling machine works correctly at the 428 gram setting. It is believed that the machine is underfilling or overfilling the bags. A 46 bag sample had a mean of 433 grams. Assume the population variance is known to be 441. Is there sufficient evidence at the 0.01 level that the bags are underfilled or overfilled? Step 1 of 6: State the null and alternative hypotheses. Step 2 of 6: Find the value of the test statistic. Round your answer to two decimal places. Step 3 of 6: Specify if the test is one-tailed or two-tailed. Step 4 of 6: Find the P-value of the test statistic. Round your answer to four decimal places. Step 5 of 6: Identify the level of significance for the hypothesis test. Step 6 of 6: Make the decision to reject or fail to reject the null hypothesis. Step 7 of 7: State the conclusion of the hypothesis test.arrow_forwardFor each of the following investigations, state i) null hypothesis, ii) alternative hypothesis and iii) type of test, two sided/one sided. a) You wish to investigate if income from tobacco farming is greater than that of from tea farming in Malawi. b) You want to compare proportion of army worms killed by Doom those killed by Attack pesticide.arrow_forward
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