Confidence intervals for sample; Cohen's guidelines, two-tai

8.22. Calculate the 95% confidence interval for the following fictional data regarding daily TV viewing habits: µ = 4.7; σ = 1.3 hours; sample of 78 people with a mean of 4.1 hours.

8.30. For each of the following d values, identify the size of the effect using Cohen's guidelines. (a) d = 0.79 (b) d = - 0.43 (c) d = 0.22 (d) d = -0.04

8.32. For each of the following z statistics, calculate the p value for a two-tailed test. (a) 2.23 (b) -1.82 (c) 0.33

8.34. For each of the three z statistics you considered in number 8.32 as a two-tailed test, determine Prep: (a) 2.23 (b) -1.82 (c) 0.33

8.48. Let's assume the average speed of a serve in women's tennis is around 118 mph with a standard deviation of 12 mph. We recruit 26 amateur tennis players to use our method this time, and after six months we calculate a group mean of 123 mph.
(a) Using a 95% confidence interval, test the hypothesis that our method makes a difference. (b) Compute the effect size and describe its strength.

2. Each of the following is a confidence interval for μ = true average (i.e., population mean) resonance frequency (Hz) for all tennis rackets of a certain type:
(114.4. 115.6) (114.1,115.9)
a. What is the value of the sample mean resonance frequency?
b. Both intervals were calculated from the same sample data. The confi

Using the spread sheet that is attached, develop 95% and 99% confidenceintervalsfor the following:
The mean hours per week that individuals spend in their vehicles,the average number of miles driven per week, the proportion of individuals who are satisfied with their vehicle and the proportion of individuals who have at least

Suppose that, for a sample size n = -100 measurements, we find that x = 50. Assuming that the standard deviation equals 2, calculate confidenceintervalsfor the population mean with the following confidence levels:
a) 95% b) 99% c) 97% d) 80% e) 99.73% f) 92%

Suppose that for a small sample of n = 11 measurements, we find that x- = 72 and s = 5. Assuming normality, compute confidenceintervalsfor the population mean u with the following levels of confidence.
a. 95%
b. 99%
c. 80%
d. 90%
e. 98%
f. 99.8%

Sales personnel for Skillings Distributors submit weekly reports listing the customer contacts made during the week. A sample of 65 weekly reports showed a sample mean of 19.5 customer contacts per week. The sample standard deviation was 5.2. Provide 90% and 95% confidenceintervalsfor the population mean number of weekly custo

Most water treatment facilities monitor the quality of their drinking water on an hourly basis. One variable monitored is pH, which measures the degree of alkalinity or acidity in the water. A target pH level is 8.5. pH values below 8.5 is acidic and above 8.5 is alkaline, both of which are bad for health. A random sample of

1. You are given the sample mean and the sample standard deviation. use this information to construct the 90% and 95% confidenceintervalsfor the population mean. Which interval is wider?
A random sample of 32 gas grills has a mean price of $630.90 and a standard deviation of $56.70.
A random sample of 156 fields of durum

In order to determine the fuel efficiency for the Subaru Impreza the following information was gathered:
a) A random sample of 12 Imprezas were driven yielding the following miles per gallon (mpg).
25.1 24.6 22.5 27.8 26.1 21.0 23.9 28.4 24.4 23.5 26.2 20.7
Create a 95% confidence interval estimate