Question

1. Provide an appropriate response.
   
   A district administrator wants to determine the effect of truancy on academic achievement. She asks the dean at a high school to randomly select the records of 50 truant students and to randomly select the records of 50 nontruant students. Identify any problems that are likely to cause confounding.

   		the use of records from only one school
   		nothing (this is a well-designed retrospective study)
   		the use of one person to select the records for members of both groups
   		the number of records in each group (since, presumably, there are more nontruant students, there should be more members selected from that group)

2 points

Question 40

1. Identify which of these types of sampling is used: random, stratified, systematic, cluster, convenience.
   
   To avoid working late, a quality control analyst simply inspects the first 100 items produced in a day.

   		Random
   		Convenience
   		Cluster
   		Stratified
   		Systematic

2 points

Question 41

1. Construct the requested table. Round relative frequencies to the nearest hundredth of a percent, unless otherwise indicated.
   
   The following data show the body temperatures (°F) of randomly selected subjects. Construct a relative frequency table with seven classes: 96.9 - 97.2, 97.3 - 97.6, 97.7 - 98.0, and so on.
   
   Round relative frequencies to the nearest tenth of a percent.

2 points

Question 42

1. Construct the requested table.
   
   The following data represent the total number of years of formal education for 40 employees of a bank.
   
   
   
   Create a frequency table for the number of years of education.

2 points

Question 43

1. Determine whether the evaluated group is a population or a sample.
   
   A researcher determines that 42.7% of all downtown office buildings have ventilation problems.

   		Population
   		Sample

2 points

Question 44

1. Determine whether the evaluated group is a population or a sample.
   
   A researcher examines the records of all the registered voters in one city and finds that 43% are registered Democrats.

   		Sample
   		Population

2 points

Question 45

1. Provide a written description of the complement of the given event.
   
   Of ten adults, at least one of them has high blood pressure.

   		None of the adults have high blood pressure.
   		At most one of the adults has high blood pressure.
   		All of the adults have high blood pressure.
   		Nine of the adults have high blood pressure.

2 points

Question 46

1. Provide a written description of the complement of the given event.
   
   When several textbooks are edited, none of them are found to be free of errors.

   		All of the textbooks are free of errors.
   		One of the textbooks is free of errors.
   		At least one of the textbooks is free of errors.
   		At most one of the textbooks is free of errors.

2 points

Question 47

1. Find the variance for the given data. Round your answer to one more decimal place than the original data. To get the best deal on a microwave oven, Jeremy called six appliance stores and asked the cost of a specific model. The prices he was quoted are listed below:
   

   $663

   $273

   $410

   $622

   $174

   $374

   		36,838.3 dollars2
   		1,207,582.7 dollars2
   		30,698.6 dollars2
   		36,838.2 dollars2

2 points

Question 48

1. Find the standard deviation for the given data. Round your answer to one more decimal place than the original data.
   
   The numbers listed below represent the amount of precipitation (in inches) last year in six different U.S. cities.

   17.2​

   16.6​

   30.8​

   28.6​

   20.3​

   18.4

   		6.15 in.
   		3088.7 in.
   		2899.6 in.
   		29.7 in.

2 points

Question 49

1. Determine if the outcome is unusual. Consider as unusual any result that differs from the mean by more than 2 standard deviations. That is, unusual values are either less than μ - 2σ or greater than μ + 2σ.
   
   A survey for brand recognition is done and it is determined that 68% of consumers have heard of Dull Computer Company. A survey of 800 randomly selected consumers is to be conducted. For such groups of 800, would it be unusual to get 504 consumers who recognize the Dull Computer Company name?

   		Yes
   		No

2 points

Question 50

1. Find the standard deviation, σ, for the binomial distribution which has the stated values of n and p. Round your answer to the nearest hundredth.
   
   n = 1617; p = 0.57

   		σ = 17.50
   		σ = 24.03
   		σ = 23.18
   		σ = 19.91

Answer 1

39.

Random samples of high schools of district should be taken. The problems that are likely to cause confounding.

the use of records from only one school

Question 40

Simply inspecting the first 100 items produced in a day is an example of Convenience sampling

Convenience

Question 41 and 42

No data

Question 43

It is a population because 42.7% of all downtown office buildings have ventilation problems.

Population

Question 44

It is a population because the records of all the registered voters in one city were examined.

Population

Question 45

The complement is of ten adults, none of them has high blood pressure.

None of the adults have high blood pressure.

Question 46

The complement is - when several textbooks are edited, at least one of them are found to be free of errors.

At least one of the textbooks is free of errors.

Question 47

$663

$273

$410

$622

$174

$374

Mean = (663 + 273 + 410 + 622 + 174 + 374) / 6 = 419.3333

Variance = ((663 - 419.3333)^2 + (273 - 419.3333)^2 + (410 - 419.3333)^2 + (622 - 419.3333)^2 + (174 - 419.3333)^2 + (374 - 419.3333)^2 ) / (6-1)

= $36838.3

36,838.3 dollars2

Question 48

17.2​

16.6​

30.8​

28.6​

20.3​

18.4

Mean = (17.2 + 16.6 + 30.8 + 28.6 + 20.3 + 18.4) / 6 = 21.98333

Variance = (17.2 - 21.98333)^2 + (16.6 - 21.98333)^2 + (30.8 - 21.98333)^2 + (28.6 - 21.98333)^2 + (20.3 - 21.98333)^2 + (18.4 - 21.98333)^2 ) / (6-1)

= 37.80967

Standard deviation = = 6.15

6.15 in.

Question 49

Standard error of proportion, SE = = 0.01649242

Sample proportion = 504 / 800 = 0.63

Z Score = (0.63 - 0.68) / 0.01649242 = -3.03

Since Z score does not lie between -2 and +2, the data is unusual.

Yes

Question 50

n = 1617; p = 0.57

Standard deviation = = 19.91

σ = 19.91