STAT200 Week 2 Homework

Question: #8727

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

Blue

Green

Gray

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.

Solution: #8754

STAT200 Week 2 Homework

7. For the data from the 1977 Stat. and Biom. 200 class for eye color, construct: Eye Color Number of Students Brown 11 Blue 10 Green 4 Gray 1 pie graph horizontal bar graph vertical bar graph a frequency table with the relative frequency of each eye color Eye Color Number of Students R Fi Brown 11 0.423 Blue 10 0.385 Green 4 0.154 Gray 1 0.038 26 1.000 9. Which of the box plots on the graph has a large positive skew? Which has a large negative skew? The Boxplot is an Indicator of Symmetry. If the line is close to the center of the box and the whisker lengths are the same then sample is from a symmetric population. If the top whisker is much longer than the bottom whisker and the line is gravitating towards the bottom of the box, then sample is from population which is skewed to the right. While, if the bottom whisker is much longer than the top whisker and the line is rising to the top of the box, then sample is from population which is skewed to the left. Here, Box plot B. has a large positive skew. And, Box plot C. has a large negative skew. 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 Here mean and mean trimmed 25% will change when I correct the recording error. However median will remain unaffected. Mean is defined as sum of all observations divided by total number of observations. Formuale for trimmed mean is given as μ = ∑ Xi / n Where, ∑ Xi - Sum of your Trimmed Set n - Total Numbers in Trimmed set μ - Trimmed Mean 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, interquart...