Stat 200 Week 2 Homework

7. For the data from the 1977 Stat. and Biom. 200 class for eye color, construct: 

a.       pie graph

b.      horizontal bar graph

c.       vertical bar graph

d.      a frequency table with the relative frequency of each eye color 
 

Eye Color

Number of students

Brown

11

Blue

10

Green

4

Gray

1

9. Which of the box plots below has a large positive skew? Which has a large negative skew? (relevant section & relevant section) 

 

6.      You recorded the time in seconds it took for 8 participants to solve a puzzle. These times appear below. However, when the data was entered into the statistical program, the score that was supposed to be 22.1 was entered as 21.2. You had calculated the following measures of central tendency: the mean, the median, and the mean trimmed 25%. Which of these measures of central tendency will change when you correct the recording error? 

Time (seconds)

15.2

18.8

19.3

19.7

20.2

21.8

22.1

29.4

8.      You know the minimum, the maximum, and the 25th, 50th, and 75th percentiles of a distribution. Which of the following measures of central tendency or variability can you determine? 

mean, median, mode, trimean, geometric mean,range, interquartile range, variance, standard deviation

The following questions are from the ADHD Treatment (AT) case study.

30. (AT) What is the mean number of correct responses of the participants after taking the placebo (0 mg/kg)? 

31. (AT) What are the standard deviation and the interquartile range of the d0 condition?

78. Twenty-five randomly selected students were asked the number of movies they watched the previous week. The results are as follows:

# of movies      Frequency    Relative Frequency      Cumulative Relative Frequency

       0                      5

       1                      9

       2                      6

       3                      4

       4                      1

80. If the data were collected by asking the first 111 people who entered the store, then the type of sampling is:

a. Cluster

b. Simple random

c. stratified

d. convenience

84. Given the following box plot:

Figure 2.41

a.       Which quarter has the smallest spread of data? What is that spread?

b.      Which quarter has the largest spread of data? What is that spread?

c.       Find the interquartile range (IQR).

d.      Are there more data in the interval 5–10 or in the interval 10–13? How do you know this?

e.       Which interval has the fewest data in it? How do you know this?

i.                    0–2

ii.                  2–4

iii.                10–12

iv.                12–13

v.                  need more information

88. Given the following box plots, answer the questions.

a.       In complete sentences, explain why each statement is false.

i.                    Data 1 has more data values above two than Data 2 has above two.

ii.                  The data sets cannot have the same mode.

iii.                For Data 1, there are more data values below four than there are above four.

b.      For which group, Data 1 or Data 2, is the value of “7” more likely to be an outlier? Explain why in complete sentences.