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The amount of rainfall in January in a certain city is normally distributed with a mean of 4.3 inches and a standard deviation of 0.3 inches. Find the value of the quartile Q1

X has a normal distribution with mean = 4.3 and sd = 0.3

Question 1

Assume that the weight loss for the first month of a diet program varies between 6 pounds and 12 pounds, and is spread evenly over the range of possibilities, so that there is a uniform distribution. Find the probability of the given range of pounds lost.

Less than 11 pounds

1/3

1/6

5/6

5/7

Question 2

If z is a standard normal variable, find the probability.

The probability that z is less than 1.13

0.1292

0.8708

0.8485

0.8907

Question 4 Assume that X has a normal distribution, and find the indicated probability.

The mean is 15.2 and the standard deviation is 0.9. Find the probability that X is greater than 17.

0.9713

0.9821

0.0228

0.9772

Question 5

The weights of the fish in a certain lake are normally distributed with a mean of 19 lb and a standard deviation of 6. If 4 fish are randomly selected, what is the probability that the mean weight will be between 16.6 and 22.6 lb?

0.0968

0.4032

0.6730

0.3270

Question 6

Estimate the indicated probability by using the normal distribution as an approximation to the binomial distribution.

A multiple choice test consists of 60 questions. Each question has 4 possible answers of which one is correct. If all answers are random guesses, estimate the probability of getting at least 20% correct.

0.0901

0.8508

0.3508

0.1492

Question 7

use the normal distribution to approximate the desired probability.

Find the probability that in 200 tosses of a fair die, we will obtain at least 40 fives.

0.0871

0.1210

0.2229

0.3871

Question 8

The following confidence interval is obtained for a population proportion, p: (0.707, 0.745). Use these confidence interval limits to find the margin of error, E.

0.038

0.017

0.019

0.020

Question 9

Assume that a sample is used to estimate a population proportion p. Find the margin of error E that corresponds to the given statistics and confidence level. Round the margin of error to four decimal places.

95% confidence; the sample size is 10,000, of which 40% are successes

0.0072

0.0110

0.0126

0.0096

Question 10

use the given degree of confidence and sample data to construct a confidence interval for the population proportion p.

n = 110, x = 55; 88% confidence

0.425 < p < 0.575

0.421 < p < 0.579

0.422 < p < 0.578

0.426 < p < 0.574

Question 11

use the given data to find the minimum sample size required to estimate the population proportion.

Margin of error: 0.05; confidence level: 99%; from a prior study, PHAT is estimated by 0.15.

17

339

407

196

Question 12

430 randomly selected light bulbs were tested in a laboratory, 224 lasted more than 500 hours. Find a point estimate of the proportion of all light bulbs that last more than 500 hours.

0.521

0.519

0.479

0.343

Question 13

use the given degree of confidence and sample data to construct a confidence interval for the population proportion p.

When 319 college students are randomly selected and surveyed, it is found that 120 own a car. Find a 99% confidence interval for the true proportion of all college students who own a car.

0.313 < p < 0.439

0.332 < p < 0.421

0.323 < p < 0.429

0.306 < p < 0.446

Question 14

In a certain population, body weights are normally distributed. Not knowing the sample mean or standard deviation, how many people must be surveyed? Assume that we want 96% confidence that the error is no more than 4 percentage points.

660

317

501

232

Question 15

use the confidence level and sample data to find the margin of error E. Round your answer to the same number of decimal places as the sample mean unless otherwise noted.

College students’ annual earnings: 99% confidence; n = 76, W3T15

$196

$891

$233

$258

Question 16

use the confidence level and sample data to find a confidence interval for estimating the population mu. Round your answer to the same number of decimal places as the sample mean.

A random sample of 105 light bulbs had a mean life of 441 hours with a standard deviation of 40 hours. Construct a 90% confidence interval for the mean life, mu, of all light bulbs of this type.

433 hr < mu < 449 hr

435 hr < mu < 447 hr

431 hr < mu < 451 hr

432 hr < mu < 450 hr

Question 17

use the given information to find the minimum sample size required to estimate an unknown population mean mu.

How many women must be randomly selected to estimate the mean weight of women in one age group. We want 90% confidence that the sample mean is within 3.7 lb of the population mean, and the population standard deviation is known to be 28 lb.

221

156

153

155

Question 18

Assume that a sample is used to estimate a population mean mu. Use the given confidence level and sample data to find the margin of error. Assume that the sample is a simple random sample and the population has a normal distribution. Round your answer to one more decimal place than the sample standard deviation.

95% confidence; n = 21; x-bar = 0.16; s = 0.16

0.085

0.068

0.063

0.073

Question 19

use the given degree of confidence and sample data to construct a confidence interval for the population mean mu. Assume that the population has a normal distribution.

Thirty randomly selected students took the calculus final. If the sample mean was 83 and the standard deviation was 13.5, construct a 99% confidence interval for the mean score of all students.

76.21 < mu < 89.79

76.23 < mu < 89.77

76.93 < mu < 89.07

78.81 < mu < 87.19

Question 20

Find the critical value CRITl corresponding to a sample size of 24 and a confidence level of 95 percent.

35.172

13.091

11.689

38.076

Question 1

Determine which of the four levels of measurement (nominal, ordinal, interval, ratio) is most appropriate.

Nationalities of survey respondents.

Nominal

Ordinal

Ratio

Interval

5 points

Question 2

Perform the requested conversions. Round decimals to the nearest thousandth and percents to the nearest tenth of a percent, if necessary.

Convert the fraction 7/11 to an equivalent decimal and percentage.

0.756, 75.6%

0.636, 63.6%

0.636, 6.36%

0.756, 756%

5 points

Question 3

Identify which of these types of sampling is used: random, stratified, systematic, cluster, convenience.

49, 34, and 48 students are selected from the Sophomore, Junior, and Senior classes with 496, 348, and 481 students respectively.

Random

Cluster

Systematic

Stratified

Convenience

Question 4

Identify the type of observational study (cross-sectional, retrospective, prospective).

A town obtains current employment data by polling 10,000 of its citizens this month.

Cross-sectional

Prospective

Retrospective

None of these

Question 5

Provide an appropriate response.

The following frequency distribution analyzes the scores on a math test. Find the class midpoint of scores interval 40-59.

Question 9

Find the mean for the given sample data. unless indicated otherwise, round your answer to one more decimal place than is present in the original data values.

The local Tupperware dealers earned these commissions last month:

$1077.28, $2661.13, $4642.11, $4264.15, $1019.55, $3444.20, $2525.92, $3740.26, $3533.07, $1633.84

What was the mean commission earned? Round your answer to the nearest cent.

$3171.28

$2848.15

$3567.69

$2854.15

Question 10

Find the median for the given sample data.

The distances (in miles) driven in the past week by each of a company’s sales representatives are listed below.

107, 114, 214, 230, 436, 445

Find the median distance driven.

222 mi

220.50 mi

230 mi

214 mi

5 points

Question 11

Find the midrange for the given sample data.

The speeds (in mph) of the cars passing a certain checkpoint are measured by radar. The results are shown below. Find the midrange.

44.3, 41.4, 42.4, 40.7, 43.1, 40.3, 44.5, 41.4, 44.3, 42.1 43.4 41.4 40.7 43.4 41.4

4.20 mph

42.30 mph

42.1 mph

42.40 mph

Question 12

A student earned grades of C, A, B, and A. Those courses had these corresponding numbers of credit hours: 4, 5, 1, and 5. The grading system assigns quality points to letter grades as follows: A=4, B=3, C=2, D=1, and F=0. Compute the grade point average (GPA) and round the result to two decimal places.

8.75

2.18

3.50

3.40

Question 13

Find the range for the given sample data.

The manager of an electrical supply store measured the diameters of the rolls of wire in the inventory. The diameters of the rolls (in meters) are listed below.

0.177, 0.115, 0.542, 0.413, 0.618, 0.315

0.503 m

0.138 m

0.115 m

0.542 m

Question 14

Find the variance for the given data. Round your answer to one more decimal place than the original data.

The weights (in ounces) of 10 cookies are shown.

1.47, 0.56, 0.58, 0.86, 1.21, 1, 1.46, 1.44, 0.88, 0.53

0.118 oz^2

0.144 oz^2

0.13 oz^2

0.108 oz^2

Question 15

Find the standard deviation for the given sample data. Round your answer to one more decimal place than is present in the original data.

Listed below are the amounts of time (in months) that the employees of a restaurant have been working at the restaurant.

2, 3, 5, 13, 22, 35, 60, 86, 101, 122

43.3 months

42.2 months

45.8 months

44.5 months

Question 16

use the empirical rule to solve the problem.

At one college, GPA’s are normally distributed with a mean of 2.9 and a standard deviation of 0.6. What percentage of students at the college have a GPA between 2.3 and 3.5?

99.7%

84.13%

68%

95%

Question 17

The mean of a set of data is -3.82 and its standard deviation is 2.31. Find the z score for a value of 3.99.

3.04

3.72

3.68

3.38

Question 18

Find the percentile for the data value.

Data set: 122, 134, 126, 120, 128, 130, 120, 118, 125, 122, 126, 136, 118, 122, 124, 119

data value: 128

75

85

62

70

Question 19

Find the indicated measure.

The weights (in pounds) of 30 newborn babies are listed below. Find Q1.

5.5, 5.7, 5.8, 6.0, 6.1, 6.1, 6.3, 6.4, 6.5, 6.6, 6.7, 6.7, 6.7, 6.9, 7.0, 7.0, 7.0, 7.1, 7.2, 7.2, 7.4, 7.5, 7.7, 7.7, 7.8, 8.0, 8.1, 8.1, 8.3, 8.7

7.5 lb

6.4 lb

5.8 lb

6.3 lb

Question 20

Find the indicated measure.

The test scores of 32 students are listed below. Find P46.

32, 37, 41, 44, 46, 48, 53, 55, 56, 57, 59, 63, 65, 66, 68, 69, 70, 71, 74, 74, 75, 77, 78, 79, 80, 82, 83, 86, 89, 92, 95, 99

14.72

67

68

15