Scientists are interested in the placebo effect on adults with arthritis. They randomly choose 15 adults with arthritis and give them 2 treatments: effective drug and placebo for 1 week at different times. At the end of each week, the scientists ask the participants to rate their arthritic pain level on a scale of 1-5, where 1 is little pain and 5 is a lot of pain. The researchers then take the difference of their pain levels (affective drug - placebo). The data are below. 0, 1, -2, 1, 0, -1, 3, 1, 1, –1, 0, 1, -2, –1, -7 A USE SALT (a) Find the 5-number summary for the difference of arthritic pain levels. Minimum = -7 Q, = -1 Median = Q2 = Maximum = 3 1 (b) One of the conditions for inference for population mean difference of paired data is normality. Outliers within a data set cast a shadow of doubt upon the normality of the population distribution. Use the 5-number summary calculated in part (a) to determine if there are any outliers in the data set. Which of the values, if any, is an outlier according to the outlier rule? (Select all that apply.) 2 -7 O -2 O 1 O 3 O none of the data values are outliers (c) Despite your answer to part (b), assume the conditions for inference have been met. Using the sample standard deviation, s, = 2.26, calculate a 95% confidence interval for the true mean difference of arthritic pain levels. (Use a table or SALT. Round your answers to two decimal places.) 0.32 A confidence interval is of the form Point estimate + Margin of Error., 2.61 A confidence interval is of the form Point estimate + Margin of Error.

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Scientists are interested in the placebo effect on adults with arthritis. They randomly choose 15 adults with arthritis and give them 2 treatments: effective drug and placebo for 1 week at different times. At the end of each
week, the scientists ask the participants to rate their arthritic pain level on a scale of 1-5, where 1 is little pain and 5 is a lot of pain. The researchers then take the difference of their pain levels (affective drug - placebo).
The data are below.
0, 1, -2, 1, 0, -1, 3, 1, 1, -1, 0, 1, -2, -1, -7
n USE SALT
(a) Find the 5-number summary for the difference of arthritic pain levels.
Minimum = |-7
Q, = |-1
Median = 0
1
Maximum = 3
(b) One of the conditions for inference for population mean difference of paired data is normality. Outliers within a data set cast a shadow of doubt upon the normality of the population distribution.
Use the 5-number summary calculated in part (a) to determine if there are any outliers in the data set. Which of the values, if any, is an outlier according to the outlier rule? (Select all that apply.)
V -7
-2
O 1
O 3
O none of the data values are outliers
(c) Despite your answer to part (b), assume the conditions for inference have been met. Using the sample standard deviation, s, = 2.26, calculate a 95% confidence interval for the true mean difference of arthritic pain
levels. (Use a table or SALT. Round your answers to two decimal places.)
0.32
A confidence interval is of the form Point estimate + Margin of Error., 2.61
A confidence interval is of the form Point estimate + Margin of Error
(d) What would happen if the scientists increased the sample size? Continue to assume that the conditions for inference have been met. Using the sample standard deviation of s, = 2.26, and the same point estimate,
calculate a 95% confidence interval for the true mean difference of arthritic pain levels if a sample size of 20 were used. (Use a table or SALT. Round your answers to two decimal places.)
0.48
A confidence interval is of the form Point estimate + Margin of Error., 2.46
A confidence interval is of the form Point estimate + Margin of Error.
Transcribed Image Text:Scientists are interested in the placebo effect on adults with arthritis. They randomly choose 15 adults with arthritis and give them 2 treatments: effective drug and placebo for 1 week at different times. At the end of each week, the scientists ask the participants to rate their arthritic pain level on a scale of 1-5, where 1 is little pain and 5 is a lot of pain. The researchers then take the difference of their pain levels (affective drug - placebo). The data are below. 0, 1, -2, 1, 0, -1, 3, 1, 1, -1, 0, 1, -2, -1, -7 n USE SALT (a) Find the 5-number summary for the difference of arthritic pain levels. Minimum = |-7 Q, = |-1 Median = 0 1 Maximum = 3 (b) One of the conditions for inference for population mean difference of paired data is normality. Outliers within a data set cast a shadow of doubt upon the normality of the population distribution. Use the 5-number summary calculated in part (a) to determine if there are any outliers in the data set. Which of the values, if any, is an outlier according to the outlier rule? (Select all that apply.) V -7 -2 O 1 O 3 O none of the data values are outliers (c) Despite your answer to part (b), assume the conditions for inference have been met. Using the sample standard deviation, s, = 2.26, calculate a 95% confidence interval for the true mean difference of arthritic pain levels. (Use a table or SALT. Round your answers to two decimal places.) 0.32 A confidence interval is of the form Point estimate + Margin of Error., 2.61 A confidence interval is of the form Point estimate + Margin of Error (d) What would happen if the scientists increased the sample size? Continue to assume that the conditions for inference have been met. Using the sample standard deviation of s, = 2.26, and the same point estimate, calculate a 95% confidence interval for the true mean difference of arthritic pain levels if a sample size of 20 were used. (Use a table or SALT. Round your answers to two decimal places.) 0.48 A confidence interval is of the form Point estimate + Margin of Error., 2.46 A confidence interval is of the form Point estimate + Margin of Error.
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What would happen if the scientists increased the sample size? Continue to assume that the conditions for inference have been met. Using the sample standard deviation of 

sd = 2.26,

 and the same point estimate, calculate a 95% confidence interval for the true mean difference of arthritic pain levels if a sample size of 30 were used. (Use a table or technology. Round your answers to two decimal places.)

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