Statistical analysis exam 6 | Algebra homework help

/in /by

The data set represents the income levels of the members of a country club. Estimate the probability that a randomly selected member earns at least $98,000.

112,000 126,000 90,000 133,000 94,000 112,000 98,000 82,000 147,000 182,000 86,000 105,000

140,000 94,000 126,000 119,000 98,000 154,000 78,000 119,000

A. 0.4

  

B. 0.6

  

C. 0.66

  

D. 0.7
Question 13 of 40
 2.5 Points
Suppose you have an extremely unfair die: The probability of a 6 is 3/8, and the probability of each other number is 1/8. If you toss the die 32 times, how many twos do you expect to see?

Question 14 of 40
 2.5 Points

The distribution of B.A. degrees conferred by a local college is listed below, by major.

Major                    Frequency
English                 2073

Mathematics        2164

Chemistry            318

Physics                856

Liberal Arts          1358

Business              1676

Engineering          868
                             9313

What is the probability that a randomly selected degree is not in Business? 
 

A. 0.7800

  

B. 0.8200

  

C. 0.8300

  

D. 0.9200

  

Reset Selection

What’s This?

Question 15 of 40
 2.5 Points
A study of two types of weed killers was done on two identical weed plots. One weed killer killed 15% more weeds than the other. This difference was significant at the 0.05 level. What does this mean?

A. The improvement was due to the fact that there were more weeds in one study.

  

B. The probability that the difference was due to chance alone is greater than 0.05.

  

C. The probability that one weed killer performed better by chance alone is less than 0.05.

  

D. There is not enough information to make any conclusion.
Question 16 of 40
 2.5 Points
Suppose you have an extremely unfair coin: the probability of a head is 1/3 and the probability of a tail is 2/3. If you toss the coin 72 times, how many heads do you expect to see?

A. 12

  

B. 22

  

C. 24

  

D. 26
Question 17 of 40
 2.5 Points
If you flip a coin three times, the possible outcomes are HHH, HHT, HTH, HTT, THH, THT, TTH, TTT. What is the probability of getting at least two tails?

A. 1/2

  

B. 2/3

  

C. 3/4

  

D. 4/9
Question 18 of 40
 2.5 Points
A sample space consists of 46 separate events that are equally likely. What is the probability of each?

A. 1/24

  

B. 1/46

  

C. 1/32

  

D. 1/18
Question 19 of 40
 2.5 Points
In a poll, respondents were asked whether they had ever been in a car accident. 220 respondents indicated that they had been in a car accident and 370 respondents said that they had not been in a car accident. If one of these respondents is randomly selected, what is the probability of getting someone who has been in a car accident? Round to the nearest thousandth.

A. 0.384

  

B. 0.380

  

C. 0.373

  

D. 0.370
Question 20 of 40
 2.5 Points
Jody checked the temperature 12 times on Monday, and the last digit of the temperature was odd six times more than it was even. On Tuesday, she checked it 18 times and the last digit was odd eight times more than it was even. Determine which series is closer to the 50/50 ratio of odd/even expected of such a series of temperature checks.

A. The Monday series is closer because 1/6 is closer to 1/2 than is 1/8.

  

B. The Monday series is closer because 6/12 is closer to 0.5 than is 8/18.

  

C. The Tuesday series is closer because the 13/18 is closer to 0.5 than is 9/12.

  

D. The series closest to the theoretical 50/50 cannot be determined without knowing the number of odds and evens in each series.
Question 21 of 40
 2.5 Points

Eleven female college students are selected at random and asked their heights. The heights (in inches) are as follows:

67, 59, 64, 69, 65, 65, 66, 64, 62, 64, 62

Estimate the mean height of all female students at this college. Round your answer to the nearest tenth of an inch if necessary.

A. It is not possible to estimate the population mean from this sample data

  

B. 64.3 inches

  

C. 64.9 inches

  

D. 63.7 inches
Question 22 of 40
 2.5 Points

Suggest the cause of the correlation among the data.

The graph shows strength of coffee (y) and number of scoops used to make 10 cups of coffee (x). Identify the probable cause of the correlation.

 

A.

The variation in the x variable is a direct cause of the variation in
the y variable.

  

B. There is no correlation between the variables.

  

C. The correlation is due to a common underlying cause.

  

D. The correlation between the variables is coincidental.

  

Reset Selection

What’s This?

Question 23 of 40
 2.5 Points

The scatter plot and best-fit line show the relation among the number of cars waiting by a school (y) and the amount of time after the end of classes (x) in arbitrary units. The correlation coefficient is -0.55. Determine the amount of variation in the number of cars not explained by the variation time after school.

A. 55%

  

B. 70%

  

C. 30%

  

D. 45%

  

Reset Selection

What’s This?

Question 24 of 40
 2.5 Points

Select the best estimate of the correlation coefficient for the data depicted in the scatter diagram.

 

A. -0.9

  

B. 0.9

  

C. 0.5

  

D. -0.5

  

Reset Selection

Question 25 of 40
 2.5 Points
A population proportion is to be estimated. Estimate the minimum sample size needed to achieve a margin of error E = 0.01with a 95% degree of confidence.

A. 7,000

  

B. 8,000

  

C. 9,000

  

D. 10,000
Question 26 of 40
 2.5 Points

Which point below would be an outlier if it were on the following graph?

A. (25, 20)

  

B. (5, 12)

  

C. (7, 5)

  

D. (5, 3)

  

Reset Selection

Question 27 of 40
 2.5 Points
A researcher wishes to estimate the proportion of college students who cheat on exams. A poll of 560 college students showed that 27% of them had, or intended to, cheat on examinations. Find the 95% confidence interval.

A. 0.2323 to 0.3075

  

B. 0.2325 to 0.3075

  

C. 0.2325 to 0.3185

  

D. 0.2323 to 0.3185
Question 28 of 40
 2.5 Points
Monthly incomes of employees at a particular company have a mean of $5954. The distribution of sample means for samples of size 70 is normal with a mean of $5954 and a standard deviation of $259. Suppose you take a sample of size 70 employees from the company and find that their mean monthly income is $5747. How many standard deviations is the sample mean from the mean of the sampling distribution?

A. 0.8 standard deviations above the mean

  

B. 0.8 standard deviations below the mean

  

C. 7.3 standard deviations below the mean

  

D. 207 standard deviations below the mean
Question 29 of 40
 2.5 Points

The graph shows a measure of fitness (y) and miles walked weekly. Identify the probable cause of the correlation.

A. The correlation is coincidental.

  

B. There is a common underlying cause of the correlation.

  

C. There is no correlation between the variables.

  

D. Walking is a direct cause of the fitness.
Question 30 of 40
 2.5 Points

A random sample of 30 households was selected from a particular neighborhood. The number of cars for each household is shown below. Estimate the mean number of cars per household for the population of households in this neighborhood. Give the 95% confidence interval.

A. 1.14 to 1.88

  

B. 1.12 to 1.88

  

C. 1.12 to 1.98

  

D. 1.14 to 1.98
Question 31 of 40
 2.5 Points

The scatter plot and best-fit line show the relation among the data for the price of a stock (y) and employment (x) in arbitrary units. The correlation coefficient is 0.8. Predict the stock price for an employment value of 6.

A. 8.8

  

B. 6.2

  

C. 8.2

  

D. None of the values are correct

  

Reset Selection

What’s This?

Question 32 of 40
 2.5 Points
Among a random sample of 150 employees of a particular company, the mean commute distance is 29.6 miles. This mean lies 1.2 standard deviations above the mean of the sampling distribution. If a second sample of 150 employees is selected, what is the probability that for the second sample, the mean commute distance will be less than 29.6 miles?

A. 0.8849

  

B. 0.5

  

C. 0.1131

  

D. 0.1151
Question 33 of 40
 2.5 Points

A sample of nine students is selected from among the students taking a particular exam. The nine students were asked how much time they had spent studying for the exam and the responses (in hours) were as follows:

18, 7, 10, 13, 12, 16, 5, 20, 21

Estimate the mean study time of all students taking the exam. Round your answer to the nearest tenth of an hour if necessary.

A. 13 hours

  

B. 12.2 hours

  

C. 13.6 hours

  

D. It is not possible to estimate the population mean from this sample data
Question 34 of 40
 2.5 Points

Among a random sample of 500 college students, the mean number of hours worked per week at non-college related jobs is 14.6. This mean lies 0.4 standard deviations below the mean of the sampling distribution. If a second sample of 500 students is selected, what is the probability that for the second sample, the mean number of hours worked will be less than 14.6?

A. 0.5

  

B. 0.6179

  

C. 0.6554

  

D. 0.3446
Question 35 of 40
 2.5 Points
30% of the fifth grade students in a large school district read below grade level. The distribution of sample proportions of samples of 100 students from this population is normal with a mean of 0.30 and a standard deviation of 0.045. Suppose that you select a sample of 100 fifth grade students from this district and find that the proportion that reads below grade level in the sample is 0.36. What is the probability that a second sample would be selected with a proportion less than 0.36?

A. 0.8932

  

B. 0.8920

  

C. 0.9032

  

D. 0.9048
Question 36 of 40
 2.5 Points
A researcher wishes to estimate the proportion of college students who cheat on exams. A poll of 490 college students showed that 33% of them had, or intended to, cheat on examinations. Find the margin of error for the 95% confidence interval.

A. 0.0432

  

B. 0.0434

  

C. 0.0425

  

D. 0.0427
Question 37 of 40
 2.5 Points
Of the 6796 students in one school district, 1537 cannot read up to grade level. Among a sample of 812 of the students from this school district, 211 cannot read up to grade level. Find the sample proportion of students who cannot read up to grade level.

A. 0.14

  

B. 0.26

  

C. 211

  

D. 0.23
Question 38 of 40
 2.5 Points
In a poll of 400 voters in a certain state, 61% said that they opposed a voter ID bill that might hinder some legitimate voters from voting. The margin of error in the poll was reported as 4 percentage points (with a 95% degree of confidence). Which statement is correct?

A. The reported margin of error is consistent with the sample size.

  

B. There is not enough information to determine whether the margin of error is consistent with the sample size.

  

C. The sample size is too small to achieve the stated margin of error.

  

D. For the given sample size, the margin of error should be smaller than stated.
Question 39 of 40
 2.5 Points
A researcher wishes to estimate the mean amount of money spent per month on food by households in a certain neighborhood. She desires a margin of error of $30. Past studies suggest that a population standard deviation of $248 is reasonable. Estimate the minimum sample size needed to estimate the population mean with the stated accuracy.

A. 274

  

B. 284

  

C. 264

  

D. 272
Question 40 of 40
 2.5 Points

Write possible coordinates for the single outlier such that it would no longer be an outlier.

A. (23, 18)

  

B. (20, 5)

  

C. (15, 15)

  

D. (12, 15)

  

Reset Selection