STA258 Week 4 Practice Questions
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STA258 Week 4 Practice Questions
1. According to a University of Michigan study, many adults have experienced lingering “fright” effects from a scary movie or TV show they saw as a teenager. In a survey of 150 college students, 39 said that they still experience “residual anxiety” from a TV show or movie.
a. Give a point estimate of for the true proportion of college students who experience “residual anxiety” from a scary TV show or movie.
b. Find a 95% confidence interval for p.
c. Interpret the interval you found in part b.
2. A sample of 15 psychology students rated “The Training Game” as a “great” method of understanding the animal’s perspective during the training on a 7-point scale
(where 1 = strongly disagree to 7 = strongly agree). The mean response was 5.87, with standard deviation of 1.51.
a. Construct a 95% confidence interval for the true mean response ofthe students.
b. Interpret the interval you found in part a.
c. Suppose you want to reduce the width of the 95% confidence interval to half ofthe size obtained in part a. How many students are required in the sample in order to obtain the desired confidence interval width?
3. Jitter is a term used to describe a variation in conduction time of a water power system. Low throughput jitter is successful to waterline technology. An investigation of throughput jitter in the opening switch of prototype system (Journal of Applied Physics) yielded the following descriptive statistics on conduction time for n = 18 trials: = 334.8 nanoseconds, = 6.3 nanoseconds. Conduction times is defined as the length of time is required for the downstream current to equal 10% of upstream current.
a. Construct a 95% confidence interval for the true standard deviation of conduction times of the prototype system.
b. Practically interpret the confidence interval in part a.
2022-03-11