Let x = 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 = 3.0. 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. Find the requested confidence interval for the population variance. (Round your answers to two decimal places.) lower and upper limit

A new study has found that, on average, 6- to 12-year-old children are spending less time on household chores today compared to 1981 levels. Suppose two samples representative of the study's results report the following summary statistics for the two periods. 1981 Levels 2008 Levels 24 minutes 19 minutes 51 = 3.5 minutes 52 - 4.3 minutes ni = 30 n2 - 30 Which of the following is the correct value of the test statistic assuming that the unknown population variances are equal? Multiple Cholce Z = -4.94 tss = 4.94 Z = 4.94 t59 = -4.94

The weights of 1,000 men in a certain town follow a normal distribution with a mean of 150 pounds and a standard deviation of 15 pounds.    From the data, we can conclude that the number of men weighing more than 165 pounds is about , and the number of men weighing less than 135 pounds is about .

A company is doing a hypothesis test on the variation in quality from two suppliers. Both distributions are normal, and the populations are independent. Use a = 0.05. A sample of 31 products were selected from Supplier 1 and a standard deviation of quality was found to be 3.77. A sample of 16 products were selected from Supplier 2 and a standard deviation of quality was found to be 3.5659. Test to see if the variance in quality for Supplier 1 is larger than Supplier 2. What are the correct hypotheses? Note this may view better in full screen mode. Select the correct symbols in the order they appear in the problem. Ho: 0.² H₁: 0.² Based on the hypotheses, compute the following: Round answers to at least 4 decimal places. The test statistic is = The p-value is = The decision is to [Fail to reject the null hypothesis The correct summary would be: There is not enough evidence to support the claim in quality for Supplier 1 is larger than Supplier 2. o that the variance

A researcher was interested in knowing if mean BMI was different between males and females. He obtained the following test results. Choose the correct interpretation of the results: F test p value = 0.03 Two sample t test, assume equal variance = 0.02 Two sample t test, assume unequal variance = 0.06 Mean BMI is higher in males than females. None Mean BMI is not significantly different between males and females. Mean BMI is significantly different between males and females.

A researcher was interested in knowing if mean BMI was different between males and females. He obtained the following test results. Choose the correct interpretation of the results: F test p value = 0.30 Two sample t test, assume equal variance = 0.02 Two sample t test, assume unequal variance = 0.61 Mean BMI is not significantly different between males and females. None Mean BMI is higher in males than females. Mean BMI is significantly different between males and females.

Suppose that the blood pressure for a randomly selected patient has an average of 22 and variance of 441. If a sample of 220 patients is selected, then what is P(-1.2 < X< 1.4) ?

The electric cooperative needs to know the mean household usage of electricity by its non-commercial customers in kWh per day.  They would like the estimate to have a maximum error of 0.14 kWh.  A previous study found that for an average family the variance is 4.84 kWh and the mean is 19.1 kWh per day.  If they are using a 80% level of confidence, how large of a sample is required to estimate the mean usage of electricity?   Question 8 options:   45 households   1959 households   949 housholds   405 households

A math teacher claims that the mean scores on a math assessment test for fourth grade boys and girls are equal. The mean score for 13 randomly selected boys is 151 with a standard deviation of 36, and the mean score for 15 randomly selected girls is 149 with a standard deviation of 34. At α = 0.01, can you reject the teacher's claim? Assume the populations are normally distributed and the population variances are equal.

A basketball coach believes that the variance of the heights of adult male basketball players is different from the variance of heights for the general population of men. The sample variance of heights, measured in inches, for a random sample of 19 basketball players is 14.22. The sample variance for a random sample of 18 other men is 34.49. Assume that both population distributions are approximately normal and test the coach’s claim using a 0.10 level of significance. Does the evidence support the coach’s claim? Let male basketball players be Population 1 and men in general be Population 2.   Step 1 of 3:  State the null and alternative hypotheses for the test. Fill in the blank below. H0: σ21=σ22: Ha: σ21⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯σ22 Step 2 of 3:  Compute the value of the test statistic. Round your answer to four decimal places. Step 3 of 3:  Draw a conclusion and interpret the decision.