AnswersAA - F26 Advanced AlgebraApplications with Standard Normal Distribution

Applications with Standard Normal Distribution — Unit test Answers

12 verified answers2 views
1
Free Preview

The stemplot displays 26 students’ scores on a 90-point statistics test.

Question illustration
A
23%
B
54%
C
77%
D
96%
2
Free Preview

A brand of frozen green beans lists a weight of 32 ounces on its bag. Because of variability in the manufacturing process, the bags often contain slightly more, or less, than 32 ounces of green beans. An inspector takes a random sample of 25 bags of green beans and records their weights. The weights and their relative frequencies are summarized in the histogram below.

Question illustration
A
31.9–32.0 ounces
B
32.0–32.1 ounces
C
32.1–32.2 ounces
D
32.2–32.3 ounces
3

An indoor running track is 200 meters in length. During a 3,000-meter race, runners must complete 15 laps of the track. An electronic timing device records the time it takes each runner to complete a lap for every lap in the race. These are called lap times. The histogram below displays the lap times for Stefano, a runner in the 3,000-meter race.

Question illustration
A
There were no lap times between 35 and 36 seconds.
B
There were six laps with times less than 37 seconds.
C
There were three laps with times greater than 38 seconds.
D
The interval from 37 to 38 seconds saw the most lap times.
4

The life spans of a computer manufacturer’s hard drives are normally distributed, with a mean of 3 years 6 months and a standard deviation of 9 months. What is the probability of a randomly selected hard drive from the company lasting between 2 years 3 months and 3 years 3 months? Use the portion of the standard normal table below to help answer the question.zProbability0.000.50000.230.59100.330.62930.670.74861.000.84131.330.90821.670.95252.000.9772

A
32%
B
37%
C
42%
D
95%
5

A normal distribution of data has a mean of 90 and a standard deviation of 18. What is the approximate z-score for the value 64?

A
–3.6
B
–1.4
C
1.4
D
3.6
6

Voluntary sampling is one type of sampling method that is not probability based. This means that

A
each member of a population is equally likely to be chosen for the survey.
B
the results of the survey cannot reliably be extended and generalized.
C
the likelihood of a member of the population volunteering to be surveyed is not probable.
D
the results of the survey are not mathematically probable.
7

The proportions of multiple samples of registered voters who vote are normally distributed, with a mean proportion of 0.38 and a standard deviation of 0.0485. What is the probability that a sample chosen at random has a proportion of registered voters who vote between 0.37 and 0.39? Use the portion of the standard normal table below to help answer the question.zProbability0.000.50000.040.51600.210.58320.370.64430.380.64810.390.65171.000.8413

A
2%
B
17%
C
58%
D
65%
8

The set of life spans of an appliance is normally distributed with a mean = 48 months and a standard deviation = 8 months. What is the life span of an appliance that has a z-score of –3?

Question illustration
A
3 months
B
24 months
C
45 months
D
72 months
9

A trade school would like to measure the long-term success of its graduates after they leave the school, and emails a survey requesting information from graduates about their work experience. One question asks graduates if they are currently employed in the field they studied in school, while another asks them to share their annual salary. What type of bias is most likely to be present in the survey results?

A
This is response bias because some graduates may not provide accurate information.
B
This is question wording bias because many graduates may misunderstand the questions asked.
C
This is voluntary response bias because graduates may choose to be part of the sample.
D
This is nonresponse bias because many graduates may choose not to respond to the email survey.
10

The grades of a science test are normally distributed. Thanh finds that his grade on the test has a z-score of –2.5. Which statement must be true?

A
Thanh’s grade is 2.5 standard deviations below the mean of the test grades.
B
Thanh’s grade is 2.5 points below the mean of the test grades.
C
Thanh’s grade is 2.5 standard deviations above the mean of the test grades.
D
Thanh’s grade is 2.5 points above the mean of the test grades.
11

The times of all 15 year olds who run a certain race are approximately normally distributed with a given mean = 18 sec and standard deviation = 1.2 sec. What percentage of the runners have times less than 14.4 sec?

Question illustration
A
0.15%
B
0.30%
C
0.60%
D
2.50%
12

A supervisor finds the mean number of miles that the employees in a department live from work. He finds and . Which statement must be true?

Question illustration
A
z37 is within 1 standard deviation of the mean.
B
z37 is between 1 and 2 standard deviations of the mean.
C
z37 is between 2 and 3 standard deviations of the mean.
D
z37 is more than 3 standard deviations of the mean.

Did you find these answers helpful?

More from this Course

Quiz
15 verified answers

Unit Test

Quiz
15 verified answers

Unit Test Review

Quiz
15 verified answers

Unit Test

Applications with Standard Normal Distribution —…