The mean voltage and standard deviation of 10 batteries from each manufacturer were measured. The results are summarized in the following table. Manufacturer A Sample mean voltage (millivolts): 107 Sample standard deviation (millivolts): 4 Manufacturer B Sample mean voltage (millivolts): 105 Sample standard deviation (millivolts): 2 What type of hypothesis test should be performed? Unpaired t-test Two-tailed z-test Left-tailed z-test Paired t-test What is the test statistic? What is the number of degrees of freedom? Does sufficient evidence exist to support the claim that the voltage of the batteries made by the two manufacturers is different at the α = 0.01 significance level? Yes No

The president of an all-female school wants to know if the students at her school studied more or less, on average, than the students at a neighboring all-male school. To find out, she conducted a study. Accordingly, samples were taken at each school with the following results: All female: sample size = 43, mean study time ( hours) = 18.56, standard deviation (hours) = 4.35 All male: sample size = 38, mean study time (hours) =17.95, standard deviation (hours) = 4.87 Calculate the 95% confidence interval for the differences between population means. Use brackets write the final answer [x.xx, x.xx]

Choose the appropriate statistical test. When computing, be sure to round each answer as indicated. A dentist wonders if depression affects ratings of tooth pain. In the general population, using a scale of 1-10 with higher values indicating more pain, the average pain rating for patients with toothaches is 6.8. A sample of 30 patients that show high levels of depression have an average pain rating of 7.1 (variance 0.8). What should the dentist determine? 1. Calculate the estimated standard error. (round to 3 decimals). [st.error] 2. What is thet-obtained? (round to 3 decimals). 3. What is the t-cv? (exact value) 4. What is your conclusion? Only type "Reject" or Retain"

The void volume within a textile fabric affects comfort, flammability, and insulation properties. Permeability of a fabric refers to the accessibility of void space to the flow of a gas or liquid. An article gave summary information on air permeability (cm3/cm2/sec) for a number of different fabric types. Consider the following data on two different types of plain-weave fabric: Fabric Type Sample Size Sample Mean Sample Standard Deviation Cotton 10 51.41     0.75 Triacetate 10 132.15     3.59 Assuming that the porosity distributions for both types of fabric are normal, let's calculate a confidence interval for the difference between true average porosity for the cotton fabric and that for the acetate fabric, using a 95% confidence level. Before the appropriate t critical value can be selected, df must be determined: df =    0.5625 10  +  12.8881 10   2   (0.5625/10)2 9  +  (12.8881/10)2 9  =  1.8092 0.1849…

The mean diameter of a ball bearing produced by a certain manufacturer is 0.60 cm with a standard deviation of 0.04 cm. A sample of 25 ball bearings is randomly selected from a production run. The sample had a mean of 0.60008 and a median 0.60333. What is the standard error for the sample mean? O A. 0.00032 O B. 0.008 O C. 0.0016 O D. 0.00008 O E. 0.00333

A population has a mean μ=76 and a standard deviation σ=20. Find the mean and standard deviation of a sampling distribution of sample means with sample size n=232.       Question content area bottom Part 1 μx=enter your response here   ​(Simplify your​ answer.) Part 2 σx=enter your response here   ​(Type an integer or decimal rounded to three decimal places as​ needed.)

You are a researcher assessing self-checkout lane violations at supermarkets in a town in the southern United States. The supermarket has five (5) self-checkout lanes. The violations by each lane are as follows: Lane A: 5 violations Lane B: 10 violations Lane C: 15 violations Lane D: 20 violations Lane E: 25 violations Please calculate the following (your standard deviation is 7.91): Mean:  Standard Error of the Mean:  Please interpret your Standard Error of the Mean.