In: Statistics and Probability
Assessment – Module 4
Directions: Complete these questions and submit to the correct
Assignments folder on D2L. Please upload as a Word document (.docx)
or a .pdf.
You can print this and write in the space provided, type your
answers here, or write answers on a separate sheet of paper and
upload photos. If you upload photos, please put page numbers on
your pages and make sure the photos aren’t blurry.
Note: Sometimes the book isn’t so good at giving examples, so you
are allowed to discuss this on the discussion forum, work with
other people, or ask me for help.
1. The table below gives selling prices for 24
houses in the fictional SE Portland neighborhood of Westsellstock
in July 2016. (Numbers are in thousands of dollars.)
315
310
314
337
288
292
277
267
336
361
169
339
295
318
271
241
288
241
345
321
340
306
228
314
• Find the mean and standard deviation
of the prices of these 24 houses.
• What conditions and assumptions do you
need to check to create a confidence interval for the mean price of
houses in Westsellstock?
• To create a 95% confidence interval, we
need to know the value of t* for a sample this size. What is that
value? (Looking it up in a table is the easiest.)
• Create the 95% confidence interval.
(It’s okay if the conditions aren’t met.)
• Interpret the interval with a sentence.
(Be sure your sentence includes the context of this situation, so
it should be about house prices.)
2. A consumer advocate wants to collect a sample of jelly jars and measure the actual weight of the product in the container. He needs to collect enough data to construct a confidence interval with a margin of error of no more than 2.5 grams with 99% confidence. The standard deviation of these jars is usually 3 grams. What do you recommend for his sample size?
3. The heights of women in the fictional country of
Rohkia follow a Normal distribution. You’d like to perform a
hypothesis test to see if the average height of Rohkian women is
significantly more than 61 inches.
You select 8 women at random and measure their heights
(in inches), which are recorded in the table below.
61
61
62
64
67
63
64
62
a. Find the mean and standard deviation of the heights
in the sample. Use the correct symbols for this sample data.
b. Write hypotheses to test whether the population
height is over 61 inches.
c. Perform the calculations for the test. Please report
the value of test statistic (t) and the p-value.
d. Can we conclude the mean height of Rohkian women is
significantly greater than 61 inches? Explain why or why not. (Use
α = 0.05)