REVIEW (1st midterm exam, chapter 1-3, version 2)
A. The following data represent the legal costs (in thousands of dollars) for 31 municipalities for a specific year.
62 21 40 37 40 2 125 29 9 48 21 150 23 112 50 24
38 76 20 118 260 36 18 20 7 67 455 204 92 24 52
For your convenience,![]()
1. Compute the mean, the mode, the median, and the midrange.
(mean = 73.5, mode = 20, 21, 24, and 40, MD = 40, MR = 228.5)
2. Compute the range, the variance, and the standard deviation.
(R = 453, variance = 8506.5, standard deviation = 92.2)
3. Compute the z score for the values of 2 and 455.
(For x = 2, z = - 0.78; for x = 455, z = 4.1)
4. From part 3, can you conclude that 2 and 455 are outliers? Why?
(2 is not an outlier because its z score is not less than -3; 455 is an outlier because its z score is greater than 3.)
5. Find the 1st quartile and the 3rd quartile.
(Q1 = 21, Q3 = 92)
6. What is the percentile of 37?
(P = 44%)
7. What is the score of the 40th percentile?
(c = 12.4, round up to 13th. The 13th score is 36)
8. Construct a Boxplot and describe the shape.
(Boxplot – do it yourself. Shape – extremely right skewed)
9. Construct the interval for none outliers. Are there any outliers in the data set?
(Interval for none outliers are - 85.5, and 198.5. Outliers are 204, 260 and 455 because they are outside the interval.)
B. The data shown represent the percentage of unemployed males and females for a sample of countries of the world. Using the whole numbers as stems and the decimals as leaves, construct a back-to-back stem and leaf plot and compare the distributions of the two groups (hint: compare the central location, variation, and shape of distribution.)
Females: 8.0 8.6 7.0 8.6 8.8 6.8 9.2 5.9 7.2 4.6 5.6 7.7 8.0 8.7 4.5 6.5 3.4 9.4 2.9
Males: 5.6 4.6 2.2 5.6 3.1 5.9 6.6 8.7 6.0 5.2 5.6 4.4 7.7 6.6 6.0 4.6 3.1 4.1 7.7
Answer:
| Female Unemployment rate | Male Unemployment rate | Comparison | |
| Central location | in the 8%'s | in the 5%'s | Female Unemployment rate is higher than that of male's. |
| Variation | vary from 2.9 to 9.4%. Range = 6.5% |
vary from 2.2 to 8.7%. Range = 6.5% |
Variation is the same. |
| Shape | left skewed. | Bell shaped. |