# Statistics Homework Week 1

**Statistics Homework Week 1**

3. If you are told only that you scored in the 80th percentile, do you know from that description exactly how it was calculated? Explain.

10. For the numbers 1, 2, 4, 16, compute the following: ΣX ΣX2 (ΣX)2

17. (AT) What is the independent variable of this experiment? How many levels does it have?

18. (AT) What is the dependent variable? On what scale (nominal, ordinal, interval, ratio) was it measured?

Use the following information to answer the next three exercises: A Lake Tahoe Community College instructor is interested in the mean number of days Lake Tahoe Community College math students are absent from class during a quarter.

50. What is the population she is interested in?

a. all Lake Tahoe Community College students

b. all Lake Tahoe Community College English students

c. all Lake Tahoe Community College students in her classes

d. all Lake Tahoe Community College math students

52. The instructor’s sample produces a mean number of days absent of 3.5 days. This value is an example of a:

a. parameter.

b. data.

c. statistic.

d. variable.

72. A study was done to determine the age, number of times per week, and the duration (amount of time) of residents using a local park in San Jose. The first house in the neighborhood around the park was selected randomly and then every eighth house in the neighborhood around the park was interviewed. The sampling method was:

a. simple random

b. systematic

c. stratified

d. cluster

80. Fifty part-time students were asked how many courses they were taking this term. The (incomplete) results are shown below:

**# of Courses**

**Frequency**

**Relative Frequency**

**Cumulative Relative Frequency**

1

30

0.6

2

15

3

**Table 1.33**

b. What percent of students take exactly two courses?

c. What percent of students take one or two courses?

84. Forbes magazine published data on the best small firms in 2012. These were firms which had been publicly traded for at least a year, have a stock price of at least $5 per share, and have reported annual revenue between $5 million and $1 billion. Table 1.37 shows the ages of the chief executive officers for the first 60 ranked firms.

**Age**

**Frequency**

**Relative Frequency**

**Cumulative Relative Frequency**

40-44

3

45-49

11

50-54

13

55-59

16

**Table 1.37**

90. Seven hundred and seventy-one distance learning students at Long Beach City College responded to surveys in the 2010-11 academic years. Highlights of the summary report are listed in Table 1.39.

Have computer at home

**95%**

Unable to come to campus for classes

65%

Age 41 or over

24%

Would like LBCC to offer more DL courses

95%

Took DL classes due to a disability

17%

Live at least 16 miles from campus

13%

Took DL courses to fulfill transfer requirements

71%

**Table 1.39 LBCC Distance Learning Survey Results**

a. What percent of the students surveyed do not have a computer at home?

b. About how many students in the survey live at least 16 miles from campus?

c. If the same survey were done at Great Basin College in Elko, Nevada, do you think the percentages would be the same? Why?