Have an account?
Skip to Content
Build your own quiz
Suggestions for you
10 questions
Show Answers
See Preview
- 1. Multiple Choice
The distribution of household incomes in a small town is strongly skewed to the right. The mean income is $42,000 and the standard deviation is $24,000. The Ames family’s household income is $60,000. The z-score for the Ames family’s income is
-0.75
0.3
0.75
0.86
None of these, because z-score cannot be used unless the distribution is Normal
- 2. Multiple Choice
Jack and Jill are both enthusiastic players of a certain computer game. Over the past year, Jack’s mean score when playing the game is 12,400 with a standard deviation of 1500. During the same period, Jill’s mean score is 14,200, with a standard deviation of 2000. They devise a fair contest: each one will play the game once, and they will compare z-scores. Jack gets a score of 14,000, and Jill gets a score of 16,000. Who won the contest, and what were each of their z-scores?
Jack’s z = 1.07; Jill’s z = 1.11; Jill wins the contest
Jack’s z = 1.07; Jill’s z = 0.90; Jack wins the contest
Jack’s z = 0.94; Jill’s z = 1.11; Jill wins the contest
Jack’s z = 0.94; Jill’s z = 0.90; Jack wins the contest
Jack’s z = 0.81; Jill’s z = 0.99; Jill wins the contest
- 3. Multiple Choice
If 30 is added to every number on a list, the only one of the following that is not changed is
the mean.
the mode.
the 75th percentile.
the median.
the standard deviation.
- 4. Multiple Choice
Which of the following dot plots would best be approximated by a Normal distribution?
A
B
C
D
E
- 5. Multiple Choice
Birthweights at a local hospital have a Normal distribution with a mean of 110 oz. and a standard deviation of 15 oz. The proportion of infants with birthweights between 125 oz. and 140 oz. is about
0.136
0.270
0.477
0.636
0.819
- 6. Multiple Choice
A company produces ceramic floor tiles that are supposed to have a surface area of 16.0 square inches. Due to variability in the manufacturing process, the actual surface area has a Normal distribution with a mean of 16.1 square inches and a standard deviation of 0.2 square inches. The proportion of tiles produced by the process with surface area less than 16.0 square inches is
0.1915
0.3085
0.3173
0.4115
0.6915
- 7. Multiple Choice
The scores on a university examination are Normally distributed with a mean of 62 and a standard deviation of 11. If the bottom 5% of students will fail the course, what is the lowest mark that a student can have and still be awarded a passing grade?
40
43
44
57
62
- 8. Multiple Choice
A company produces packets of soap powder labeled "Giant Size 32 Ounces." The actual weight of soap powder in a box has a Normal distribution with a mean of 33 oz. and a standard deviation of 0.8 oz. What proportion of packets are underweight (i.e., weigh less than 32 oz.)?
0.106
0.115
0.159
0.212
0.841
- 9. Multiple Choice
The time to complete a standardized exam is approximately Normal with a mean of 70 minutes and a standard deviation of 10 minutes. How much time should be given to complete the exam so that 80% of the students will complete the exam in the time given?
61.6 minutes
78.4 minutes
79.8 minutes
84 minutes
92.8 minutes
- 10. Multiple Choice
Entomologist Heinz Kaefer has a colony of bongo spiders in his lab. There are 1000 adult spiders in the colony, and their weights are Normally distributed with mean 11 grams and standard deviation 2 grams. About how many spiders are there in the colony which weigh more than 12 grams?
117
160
310
690
840
- Answer choicesTagsAnswer choicesTags