Use the following information to find the 85% confidence interval to estimate ₁-2. Assume x is normally distributed in the populations and the variances of the populations are approximately equal. Sample 1 Sample 2 n1 = 66 n2 = 47 x₁ = 24 X₂ = 29 $1=5 $2=6 a. (6.504, 13.946) b. (-5.604, 4.396) C. (3.496, 6.504) d. (-6.504, -3.496)

An operations manager wants to know whether the maintenance of a filling machine for 2 litre milk bottles has made a difference in the average fill of the milk bottle. She randomly selects 25 bottles before the maintenance service, and 25 bottles after the maintenance service has taken place. The resulting SPSS output is shown below: Paired Samples Statistics   Mean N Std. Deviation Std. Error Mean Pair 1 After Service 2.0029 25 .01142 .00228   Before service 1.9687 25 .03193 .00639     Paired Samples Test   Paired Differences             t             df           Sig. (2- tailed)           Mean       Std. Deviation       Std. Error Mean 95% Confidence Interval of the Difference Lower Upper Pair 1 After Service – Before service   .03420   .03503   .00701   .01974   .04866   4.882   24   .000                        Question: Based on the output choose the most accurate answer

A researcher takes sample temperatures in Fahrenheit of 18 days from Pittsburgh and 16 days from Cleveland. Use the sample data shown in the table. Test the claim that the mean temperature in Pittsburgh greater than the mean temperature in Cleveland. Use a significance level of a = 0.01. Assume the populations are approximately normally distributed with unequal variances. Note that list 1 is longer than list 2, so these are 2 independent samples, not matched pairs. Pittsburgh Cleveland 99 82.1 91.2 60.4 88.1 75.5 91.8 79.5 96 73.3 90.6 57.5 91.5 63.4 69.5 64.1 88.6 78.9 89.2 93 86.2 76.7 83.9 57.5 107.1 58.4 98.5 80.7 82.2 81.4 72.4 55.2 85.2 105.3 The Null Hypotheses is: Ho: µ1 - µ2 = 0 What is the alterative hypothesis? Select the correct symbols for each space. (Note this may view better in full screen mode.) HA: µ1 - µ2 ? v Select an answer Based on these hypotheses, find the following. Round answers to 4 decimal places. Test Statistic = p-value =

A researcher is interested in whether there is a difference between male and female college students in the amount of time spent doing volunteer work for the last 6 months. The researcher gathers a random sample of college students. The amount of time volunteering is measured in hours, which is an interval level-ratio and is normally distributed. Which statistical test should be used to analyze this data? a. Multiple regression b. paired samples t-test c. independent groups t-test d. Factorial ANOVA