COURSE WORK GUIDELINES:
(1) This coursework contains TWO questions and represents 25% of the total module mark.
(2) The coursework will be done using Minitab.
(3) Your coursework must have a typed cover page with the following information: Name, KU number, Module code, and the date the coursework is due.
(4) Your work must be stapled together in the following order: cover page, the printout of the session window, the printout of the worksheet (the table), all graphs and analyses.
(5) You must submit your own work.
ASSESSMENT STRATEGY
The following Leaning Outcomes will be assessed in the coursework:
1. summarise data and present it in a useful form.
2. to use appropriate distributions in solving a given problem
3. understand the nature of a hypothesis test
4. construct confidence intervals and hypothesis tests for the mean of a single population
5. use an appropriate statistical software package for basic statistical analysis and presentation of data
Q1. (40%)
According to an article published in Reader’s Digest, 20% of people are left-handed. For 20 people selected at random, let X denote the number of people out of 20 who are left-handed.
(a) Calculate the probability that exactly four of the twenty are left-handed.
(b) Calculate the probability that less than 8 of the 20 are left-handed.
(c) Find the number of people who are left-handed such that the probability of being less than or equal to this number is about 0.8.
(d) Graph the probability distribution of X.
(e) On your printout, with a pencil, circle the value that Minitab gave you for the probability that less than 8 of the 20 would be left-handed.
(f) On your printout, with a pencil, put a star next to the value that Minitab gave you for the probability that exactly 4 of 20 would be left-handed.
(g) On your printout, with a pencil, underline the value that Minitab gave you for the number of people who are left-handed such that the probability of being less than or equal to this number is about 0.8.
Q2. (60%)
Suppose a reference librarian selected a random sample of 30 customers before starting a new information retrieval system. The retrieval times in minutes are given below.
Information Retrieval
10 15 15 10 20 15 10 20 30 15
25 5 45 22 10 27 25 22 10 30
15 5 8 15 5 36 23 17 15 10
(a) Draw a histogram to summarise the retrieval times.
(b) Test for normality.
Minitab has a normality test for determining whether a set of data is randomly selected from a Normal population. Steps are:
Stat > Basic Statistics > Normality Test
Variable: Select ‘column that stores the retrieval times’
Title: Enter a Title OK
Interpret the p-Value in the normality test.
[Use Minitab HELP if necessary.]
(c) Construct a 95% confident interval to estimate the mean retrieval time. Interpret the confidence interval.
(d) Does the sample provide sufficient evidence to conclude that mean retrieval time differs from 20 minutes? Use α = 0.05.
(e) Interpret the P-value of the test.
(f) On your printout, with a pencil, circle the p-Value in the normality test that Minitab gave you (i.e. the P value in part (b)).
(g) On your printout, with a pencil, circle the null and alternative hypotheses that Minitab gave you.
(h) On your printout, with a pencil, put a star next to the p-value that Minitab gave you (i.e. the P Value in part (e)).
(i) On your printout, with a pencil, underline the 95% confidence interval that Minitab gave you.
(j) Type your answers and comments to parts (b) – (e) above on a separate sheet of paper.
Submit your coursework in the order listed under Course Work Guidelines above. Make sure that your submission includes ALL graphs created.
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