AnswersAA - F26 Advanced AlgebraStatistical Inferences

Statistical Inferences — Unit test Answers

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1
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The table shows the height of a candle as it is continuously burned.

Question illustration
A
The candle starts at a height of 25 centimeters and burns at a rate of 0.625 centimeters per hour.
B
The candle starts at a height of 25 centimeters and burns at a rate of 2.5 centimeters per hour.
C
The candle starts at a height of 22.5 centimeters and burns at a rate of 0.625 centimeters per hour.
D
The candle starts at a height of 22.5 centimeters and burns at a rate of 2.5 centimeters per hour.
2
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The number of absences for one week for all students at a high school were compiled, and the probability distribution below was created. What is the probability in any given week that a randomly selected student will be absent no more than one day?Probability DistributionDays Absent: XProbability: P(X)00.7810.1420.0330.014050.04

A
0.08
B
0.14
C
0.78
D
0.92
3

When finding the margin of error for the mean of a normally distributed population from a sample, what is , assuming a confidence level of 74%?

Question illustration
A
0.13
B
0.26
C
0.74
D
0.87
4

The president of the math club is conducting a survey to see where the twelfth-grade class wants to go on their field trip. Instead of asking the whole class, she surveys only the twelfth-grade members of the math club. She records their choices and plans to present the results to the school principal. What type of sampling did she use?

A
systematic random sampling
B
simple random sampling
C
stratified sampling
D
convenience sampling
5

A local newspaper compiles data on the number of days, X, people in a neighborhood receive the newspaper. The probability distribution for the data is shown in the table below. What is the probability that a randomly chosen person receives the newspaper at least one day per week?

Question illustration
A
16%
B
33%
C
41%
D
83%
6

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.
7

A graph with both axes numbered 1 to 10. A line increases from 1 to 3 then decreases from 3 to 5.

Question illustration
A
f(x) = 2(x – 5)(x – 1)
B
f(x) = –2(x – 5)(x – 1)
C
f(x) = 2(x + 5)(x + 1)
D
f(x) = –2(x + 5)(x + 1)
8

Opal is collecting data on water levels in different parts of town. She notices that her sample data has a low-value outlier. Which statement must be true?

A
Removing the outlier will not change the spread of the graph of the data set.
B
Removing the outlier will not change the variance of the data set.
C
Removing the outlier will increase the variance of the data set.
D
Removing the outlier will decrease the spread of the graph of the data set.
9

A simple random sample of size n is drawn from a normally distributed population, and the mean of the sample is , while the standard deviation is s. What is the 90% confidence interval for the population mean? Use the table below to help you answer the question.Confidence Level90%95%99%z*-score1.6451.962.58

Question illustration
A
x Overbar plus-or-minus StartFraction 0.90 times s Over StartRoot n EndRoot EndFraction
Option A
B
x Overbar plus-or-minus StartFraction 1.645 times s Over StartRoot n EndRoot EndFraction
Option B
C
x Overbar plus-or-minus StartFraction 1.96 times s Over StartRoot n EndRoot EndFraction
Option C
D
x Overbar plus-or-minus StartFraction 2.58 times s Over StartRoot n EndRoot EndFraction
Option D
10

What is the formula for margin of error?

A
ME =
Option A
B
ME =
Option B
C
ME =
Option C
D
ME =
Option D
11

A gymnastics coach records the scores of a gymnast and develops the probability distribution below. What is the probability the gymnast scores a 9 or 9.5?Probability DistributionGymnastics Score: XProbability: P(X)50.025.50.0260.066.50.170.167.50.1480.188.50.189?9.50.02

A
0.02
B
0.04
C
0.12
D
0.14
12

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%
13

A utility company hires pollsters to knock on random doors in different parts of town to survey residents about the cost of their electric bill. Would this study be biased? Why or why not?

A
No, it is not biased. All residents of the town will have the opportunity to respond.
B
Yes, it is biased. Some of the residents who are surveyed may not want to respond to someone who knocks at their door.
C
No, it is not biased. All residents who are surveyed will want to respond.
D
Yes, it is biased. Only certain parts of the town were surveyed.
14

Which set of population data is the least dispersed from its mean?

A
2, 3, 2, 9
B
4, 0, 4, 0
C
6, 2, 2, 2
D
9, 3, 5, 3
15

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.

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