Question 1  Provide an appropriate response.
IQ test scores are normally distributed with a mean of 100 and a standard deviation of 15. Find the x-score that corresponds to a z-score of -1.645.


75.3


82.3


91.0


79.1

Question 2  Provide an appropriate response.
The random variable x represents the number of cars per household in a town of 1000 households. Find the probability of randomly selecting a household that has less than two cars.




0.809


0.428


0.553


0.125

Question 3  Identify the data set’s level of measurement.
numbers of touchdowns scored by a major university in five randomly selected games 

4 2 4 3 4


ordinal


nominal


ratio


interval

Question 4  Determine whether the data set is a population or a sample.
The age of each employee at a local grocery store


sample


population

Question 5  Provide an appropriate response.
Fifty percent of the people that get mail-order catalogs order something. Find the probability that exactly  two of 10 people getting these catalogs will order something.


0.200


11.250


0.001


0.044

Question 6  Provide an appropriate response.
A study of 1000 randomly selected flights of a major airline showed that 798 of the flights arrived on time. What is the probability of a flight arriving on time?













Question 7  Provide an appropriate response.
A random sample of 40 students has a test score with  = 81.5. Assume the population standard deviation is 10.2. Construct the confidence interval for the population mean, μ if c = 0.90.


(78.8, 84.2)


(71.8, 93.5)


(51.8, 92.3)


(66.3, 89.1)

Question 8 Provide an appropriate response.
A test consists of 10 true or false questions. To pass the test a student must answer at least eight questions correctly. If the student guesses on each question, what is the probability that the student will pass the test?


0.08


0.055


0.20


0.8

Question 9  Provide an appropriate response.
Find the standardized test statistic t for a sample with n = 25,  = 28, s = 3, and α = 0.005 if  Round your answer to three decimal places.


1.452


1.997


1.667


1.239






Question 10  Provide an appropriate response.
The distribution of blood types for 100 Americans is listed in the table. If one donor is selected at random, find the probability of selecting a person with blood type A+.




0.45


0.68


0.4


0.34

Question 11  Provide an appropriate response.
Eight guests are invited for dinner. How many ways can they be seated at a dinner table if the table is straight with seats only on one side?


362,880


5040


40,320


1

Question 12  Provide an appropriate response.
Assume that the random variable X is normally distributed, with mean  and standard deviation  Compute the probability P(X > 92). 


0.2420


0.1977


0.7881


0.2119

Question 13  Provide an appropriate response.
The birth weights for twins are normally distributed with a mean of 2353 grams and a standard deviation of 647 grams. Use z-scores to determine which birth weight could be considered unusual.


1200 g


2353 g


3647 g


2000 g

Question 14  Provide an appropriate response.
Use the standard normal distribution to find P(-2.25 < z < 1.25).


0.4878


0.0122


0.8822


0.8944

Question 15  Provide an appropriate response.
Find the area of the indicated region under the standard normal curve.

 


0.9032


0.0823


0.0968


0.4032

Question 16  
Use the given frequency distribution to find the
 (a) class width.
 (b) class midpoints of the first class.
 (c) class boundaries of the first class.

 Miles (per day)



(a) 1
(b) 1
(c) 1-2


(a) 2
(b) 1
(c) 1-2


(a) 1
(b) 1.5
(c) 0.5-2.5


(a) 2
(b) 1.5
(c) 0.5-2.5
Question 17  Provide an appropriate response.
The lengths of pregnancies are normally distributed with a mean of 264 days and a standard deviation of 15 days. If 36 women are randomly selected, find the probability that they have a mean pregnancy between 264 days and 266 days.


0.5517


0.2881


0.7881


0.2119
Question 18  Identify the data set’s level of measurement.
temperatures of 73 selected refrigerators


ordinal


nominal


ratio


interval

Question 19  Provide an appropriate response.
The distribution of Master’s degrees conferred by a university is listed in the table.
Assume that a student majors in only one subject.


   
What is the probability that a randomly selected student with a Master’s degree majored in English or Mathematics? Round your answer to three decimal places.


0.247


0.220


0.467


0.533

Question 20  Provide an appropriate response.
Find the area of the indicated region under the standard normal curve.

 


0.309


0.3438


0.6562


1.309

Question 21  Provide an appropriate response.
At a raffle, 10,000 tickets are sold at $5 each for three prizes valued at $4,800, $1,200, and $400. What is the expected value of one ticket?


$0.64


-$4.36


$4.36


-$0.64

Question 22  Provide an appropriate response.
If an individual is selected at random, what is the probability that he or she has a birthday in July? Ignore leap years.













Question 23  Provide an appropriate response.
In a pizza takeout restaurant, the following probability distribution was obtained. The random variable x represents the number of toppings for a large pizza. Find the mean and standard deviation.




mean: 1.30; standard deviation: 2.38


mean: 1.54; standard deviation: 1.30


mean: 1.30; standard deviation: 1.54


mean: 1.14; standard deviation: 1.04
Question 24  Provide an appropriate response.
Find the area under the standard normal curve to the right of z = 1.


0.8413


0.1587


0.5398


0.1397

Question 25  Provide an appropriate response.
A card is drawn from a standard deck of 52 playing cards. Find the probability that the card is an ace or a black card.













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