Question

Please use the skills you learned in section 9.2 for this assignment.

For this activity, you will be creating a confidence interval for the average number of hours of TV watched. Last semester, my MAT 152 online students asked the question, “How many hours of screen time do you have in a typical week?” Please use the data they collected to answer the following questions.

Data: 21, 2, 28, 30, 18, 21, 25, 20, 25, 14, 21, 25, 50, 39, 46, 20, 35, 45, 37, 46

1. Are there any outliers in this data set?
2. What calculator test (1-PropZInt, Z-Interval, or T-Interval), Excel, or StatCrunch function will you use to find the confidence interval?
3. Why do you use this test (and not one of the other 2 tests)?
4. Using a 95% confidence level, what is the confidence interval?
5. What is the point estimate for the population mean?
6. What is the margin of error?
7. Suppose you knew the standard deviation for all Americans' screen time was 4 hours. If you wanted your results to be within a margin of error of 0.25 hours, how many people would you have to survey (use a 95% confidence level)?
8. Name at least 2 ways this data could be biased and hence the confidence interval would not be a good estimate of the population mean.

Your final write-up should number (1-8) your answers to each question as well as an explanation of how you arrived at the answers. For example, please include what calculator functions or computations you are using to arrive at the confidence interval.

Answer 1

use here excel and solve all .

###yes there is outiler in this data : observation 2 is outlier ##we can use here t interval because here we don't know the standard deeviation or variance and sample size is small ##other test not because for z and other interval required sample size is greater than 30 and know variance. ##but here all the conditions of the t interval satisfy hence we have to use here t interval first calculate sample mean and standard deviation and critical value ### 95 % confidence interval point estimate is xbar and margin of error is= (Tc*(s/SQRT(20) 5.828446 xbar 28.4 T Crtitical value for 2.093 use t table 12.4537 |(xbar- (Tc*(s/SQRT(20))) lower limit 22.57155 (xbar Tc*(s/SQRT(20))) Upper limit 34.22845

###We have to calculate sample size when standard deviation is 4 and margin of error is 0.25 formula n- (Zc^2 * s^2)/(ME ^2) here s 4 and ME 0.25 983.4496 n= the required sample size is 983 ## result is bias if the sample size is too small or too large and we don't know the point estimate some time if data is normality follows then we cant do any testing hence first it should be normal