Question 1

Which of the following statements is correct?

We use parameters to estimate the value of statistics.

Parameters describe sample characteristics.

We use statistics to estimate the value of parameters.

Statistics describe population characteristics.

qUESTION 2

1. The Central Limit Theorem predicts that

a.

The sampling distribution ofxxwill be approximately normal for n > 30

b.

The sampling distribution ofwill be approximately normal for n > 30

c.

The sampling distribution of^pp^will be approximately normal for np> 10 and

n(1 p) > 10

d.

The sampling distribution ofppwill be approximately normal for np > 10 and n(1 - p) > 10

e.

both (a) and (c)

f.

both (b) and (d)

QUESTION 3

1. Suppose the number of hours employees in the United States work per week follow a normal
2. distribution with mean 34 hours and standard deviation 2.8 hours. Rowan is a welder, and the
3. number of hours he works per week is in the 96th percentile. Which of the following is the
4. number of hours he works per week, rounding to the nearest hour?

38 hours

39 hours

40 hours

41 hours

QUESTION 4

1.If IQ scores are normally distributed with a mean of 100 and standard deviation of 15, what IQ

score has 25% of scores greater than it, rounded to the nearest whole number?

QUESTION 5

1.A survey of students at CSCC revealed that the number of hours spent studying the week before final exams was normally distributed with mean 25 hours and standard deviation 7 hours.

Answer each question below, rounding to three decimal places as necessary.

(a) What proportion of CSCC students studied less than 20 hours the week before the final exams?

(b) Seventy-five percent of CSCC students studied less than what number of hours in the week before the final exams?

(c) What is the probability that a randomly selected CSCC student studied more than 28 hours in the week before the final exams?

1.(d) For a random sample of 16 CSCC students, what is the probability that the sample mean study time in the week before the final exams is more than 28 hours? Suppose the percentage of students at CSCC that use an Apple device (such as an iPad or

iPhone) is 65%. If samples of n = 130 CSCC students are taken, which of the following values

represents the standard deviation of the sampling distribution of the sample proportion?

0.0435

0.0418

0.0454

0.0436

QUESTION 7

1.The correct interpretation of 90% confidence is (Choose one)

90% of all possible population means will be included in the interval

90% of all possible sample means will be included in the interval.

We can be 90% confident that the interval includes the sample mean.

The method used to get the interval, when used over and over, produces intervals which include the true population mean 90% of the time.

QUESTION 8

1.Increasing the confidence level while holding all remaing quantities constant has what type of impact on a specific confidence interval.(Choose one)

Cannot be predicted.

The interval width remains unchanged.

The interval gets wider.

The interval gets narrower.

The center decreases.

QUESTION 9

1.A survey of 180 students is selected randomly on a large university campus. They are asked if they use a tablet in class to take notes. The result of the survey is that 92 of the 180 students responded, "yes."

For each question below, write your answer as a decimal, rounding to three decimal places as necessary.

A.Find the point estimate for hat, the proportion of all students at the university that use their laptop in class to take notes.

B. Construct a 85% confidence interval for the population proportion of students that use a laptop in class to take notes.

Lower Bound:

Upper bound:

C.What sample size is needed so that a 95% confidence interval has a margin of error of 0.05? Use the preliminary estimate given in this problem.

D.Interpret this interval in the context of the problem.

QUESTION 10

1.A 95% confidence interval for the mean customer credit card balance for a local store in dollars

is given to be 456 < < 596. Which of the following correctly gives the point estimate and

margin of error for this confidence interval?

Point estimate =546

Margin of error =50

Point estimate =501

Margin of error = 95

Point estimate =526

Margin of error =70

Point estimate =456

Margin of error =140

Question 11

In Roosevelt National Forest, the rangers took random samples of live aspen trees and measure the base circumference of each tree. Base circumference of live aspen trees are normally distributed.A sample of 20 trees had a mean circumference of 15.71 inches.The population standard deviation is 4.63 inches.To find a 95% confidence interval for the mean circumference of all aspen trees in Roosevelt National Forest from this data, the correct statistical procedure would be a

Z-Interval

1-PropZInt

T-interval

T-Test

Z-Test

QUESTION 12

1.Alice and Sydney are once again arguing about statistics.Alice has correctly determined that at the 0.01 level of significance, she will reject the null hypothesis.Sydney would like to not reject the null hypotheis at the 0.05 level of significance.Is Sydney correct about this?Why or why not?

UESTION 13

1.The grade point averages (GPAs) for 15 randomly selected CSCC students is given below.

2.1

1.2

2.7

2.0

1.8

3.3

3.0

2.6

2.8

2.7

1.0

2.6

2.1

1.7

2.4

2.

3.Assume that the population of CSCC student GPAs is normally distributed.Can you conclude that this group of students mean GPA mean is higher than 2.0?

4.

5.Which option below represents the most correct null and alternate hypotheses for this scenario?

a.

H0:=2H0:=2vs.H1:>2H1:>2

b.

H0:=2H0:=2vs.H1:2H1:2

c.

H0:2H0:2vs.H1:=2H1:=2

d.

H0:2H0:2vs.H1:<2H1:<2

QUESTION 16

1.Determine whether the outcome is a Type I error, a Type II error, or a correct decision:

H₀: = 12 vs H₁: > 12

Suppose the true value of is 12 and the null hypothesis is not rejected.

Type I error

Type II Error

Correct Decision

Not enough information

QUESTION 17

1.The heart beat of a healthy lion is approximately normally distributed with a mean = 40 beats per minute.A heart rate that is too fast or too slow could indicate a health problem.A veterinarian has removed an abscessed tooth from a young, healthy lion.As the animal slowly starts to come out of anesthetic, its heart rate (in beats per minute) is taken and recorded at random times during the next hour.

30

37

43

38

35

34

36

40

Use a 0.01 level of significance to test the claim that the population mean heart rate of this lion is not 40 beats per minute.

A.What is the value of the test statistic?Round to three decimal places if possible.

B.What is the p-value for the test?Round to three decimal places if possible.

C.Would you reject or not reject the null hypothesis?

D.Stat the conclusion in the context of the problem.

QUESTION 19

1.Darwin is very proud of himself.He has decided to not use the calculator, but to use the formula for correlation to calculate the correlation coefficient for a set of data.His value is -2.4902.Is this a legitimate value for correlation?Why or why not?

QUESTION 20

1.Is the price of an airline ticket related to the number of miles traveled? The mileage between Columbus, Ohio and 13 selected cities is given below along with the average price of an airline ticket from Columbus to that city.

Mileage

4500

1000

2000

300

350

850

1500

450

100

3100

1100

500

500

Price of Ticket

1450

690

1050

400

800

620

800

650

250

1200

650

670

725

2.

3.Using your calculator, compute the correlation between mileage and price of a ticket, rounding to three decimal places as necessary

4.

Is the price of an airline ticket related to the number of miles traveled? The mileage between Columbus, Ohio and 13 selected cities is given below along with the average price of an airline ticket from Columbus to that city.

Mileage

4500

1000

2000

300

350

850

1500

450

100

3100

1100

500

500

Price of Ticket

1450

690

1050

400

800

620

800

650

250

1200

650

670

725

(a) Using your calculator, find the least-squares regression line for predicting the ticket price using the mileage. Round your slope and intercept to three decimal places as necessary.

(b) Using the regression equation you found in part (a), predict the price of a ticket when the mileage is 1750 miles.

(c) The mileage of two trips differ by 300 miles. How much should we expect the price of tickets to differ?

QUESTION 25

1.In July, Buckeye Real Estate predicted August home sales would be 200. Buckeye Real Estate actually sold 180 homes in August. Using a smoothing constant of = 0.60, forecast the September home sales using an exponential smoothing model.