Chapter 4,5,6

A test consists of 10 true/false questions. To pass the test a student must answer at least 6 questions correctly. If a student guesses on each question, what is the probability that the student will pass the test?

0.377

In a certain town, 10% of people commute to work by bicycle. If a person is selected randomly from the town, what are the odds against selecting someone who commutes by bicycle?

9:1 C

A test subject is randomly selected and tested for the disease. What is the probability the subject has the disease given that the test result is negative?

A. 0.028

In one region, the September energy consumption levels for single family homes are found to be normally distributed with a mean of 1050 kWh and a standard deviation of 218 kWh. For a randomly selected home, find the probability that the September energy consumption levels is between 1100 and 1225 kWh.

A. 0.1971

The weights of college football players are normally distributed with a mean of 200 pounds and a standard deviation of 50 pounds. If a college football player is randomly selected, find the probability that he weighs between 170 and 220 pounds.

A. 0.3811

If one of the 1156 people is randomly selected, find the probability that the person is a man or a heavy smoker?

A. 0.554

A 6-sided die is rolled. Find P(3 or 5)

A. 1/3

Suppose you are playing a game of chance. If you bet $5 on a certain event, you will collect $115 (including your $5 bet) if you win. Find the odds used for determining the payoff.

A. 22:1

According to a college survey, 22% of all students work full time. Find the mean for the number of students who work full time in the sample size 16

A. 3.5 students

Assume that the red blood cell counts of women are normally distributed with a mean of 4.577 million cells per microliter and a standard deviation of 0.382 million cells per microliter. find the 80th percentile for the red blood cell counts of women.

A. 4.898 million cells per microliter

Evaluate the expression 10P3

A. 720

Fred and Ed each have a bag of candy containing a lemon drop (LD), a cherry drop (CD), and a lollipop (LP). Each takes out a piece from their own bag and eats it. What are the possible pairs of candies eaten?

A. LD-LD, CD-LD, LP-LP, LD-CD, CD-CD, LD-LP, LP-CD, CD-LP, LP-LD

Of the 13 different women Calvin asks for a date, at least one of them accepts. Provide a written description of the compliment of the given event.

A. None of the women accept Calvin's offer

Determine whether the events are disjoint. • Get a full-time day job as a teller with a bank • Get a full-time day job as a cashier at a store

A. Yes

For such groups of 800, would it be significant to get 634 consumers who recognize the Dull Computer Company name?

A. Yes

Is the probability of getting three or more cars that fail among six cars tested significant, determined by a cutoff value of 0.05?

A. Yes

A coin is tossed 20 times. A person who claims to have extra sensory perception is asked to predict the outcome of each flip in advance. She predicts correctly on 14 tosses. What is the probability of being correct 14 or more times by guessing? Does this seem to verify her claim? Use the normal distribution to approximate the desired probability.

B. .0582, no

Find the probability that 3 randomly selected people all have the same birthday. Ignore leap years. Round to eight decimal places.

B. 0.00000751

A baseball player has a batting average of 0.346, so the probability of a hit is 0.346. Assume that his hitting attempts are independent of each other. Assume that the batter gets up to bat 4 times in each game. Estimate the probability that in 50 consecutive games, there are at least 45 games in which the batter gets at least one hit. (hint: first find the probability that in one game the batter gets at least one hit)

B. 0.0918

A tennis player makes a successful first serve 51% of the time. If she serves 9 times, what is the probability that she gets exactly 3 successful first serves in?

B. 0.154

If z is a standard normal variable, find the probability: P(-0.73<z<2.27)

B. 0.7557

A die is rolled nine times and the number of times that two shows on the upper face is counted. If this experiment is repeated many times, find the mean for the number of twos

B. 1.5twos

Find the standard deviation for the binomial distribution with n=38 and p=0.4

B. 3.02

Identify the given random variable as being discrete or continuous. • the cost of randomly selected orange

B. Discrete

Which of the following statements is not true?

B. If the probability of an event occurring is 1.5, then it is certain that event will occur

Determine whether the events are disjoint. • Finding a ten dollar bill on the sidewalk • Finding a ten dollar bill on the grass

B. No

Would it be significant for this sample of 800 to contain 494 jawbreakers that weigh more than 0.4 ounces?

B. No

Determine whether the given procedure results in a binomial distribution. If not, state the reason why. • Rolling a single die 26 times, keeping track of the numbers that are rolled

B. Not binomial: there are more than 2 outcomes for each trial

Determine whether the given procedure results in a binomial distribution. If not, state the reason why. • spinning a roulette wheel 9 times, keeping track of the occurrences of winning number of "16"

B. The procedure results in a binomial distribution

An unbiased estimator is a statistic that targets the value of the population parameter such that the sampling distribution of the statistic has a _______ equal to the ________ of the corresponding parameter.

B. mean, mean

If one of the 255 subjects is randomly selected, find the probability that the person drinks root beer given that they are over 40

C 6/17

Assume that seven adults are randomly selected. Find the probability that fewer than 3 of the selected adults watch prime-time live

C. 0.00467

Assume that the red blood cell counts of women are normally distributed with a mean of 4.577 million cells per microliter and a standard deviation of 0.382 million cells per microliter. Find the value closest to the probability that a randomly selected woman has a red blood cell count above the normal range of 4.2 to 5.4 million cells per microliter.

C. 0.0158

Find the probability of getting three or more cars that fail among six cars tested

C. 0.046

Estimate the indicated probability by using the normal distribution as an approximation to the binomial distribution. Two percent of hair dryers produced in a certain plant are defective. Estimate the probability that of 10,000 randomly selected hair dryers, at least 21 are defective.

C. 0.0934

If we randomly select one of the customers represented in the table, what is the probability that the waiting time is at least 12 minutes or between 8 and 15 minutes?

C. 0.558

If 10 students are selected at random from the physics majors, what is the probability that no more than 6 belong to an ethnic minority?

C. 0.982

Scores on a test are normally distributed with a mean of 63.2 and a standard deviation of 11.7. Find p81, which separates the bottom 81% from the top 19%

C. 73.5

Assume that the red blood cell counts of women are normally distributed with a mean of 4.577 million cells per microliter and a standard deviation of 0.382 million cells per microliter. Approximately what percentage of women have red blood cell counts in the normal range of 4.2 to 5.4 million cells per microliter?

C. 82.31%

When 100 engines are shipped, all of them are free of defects. Select a written description of the complement of the given event.

C. At least one of the engines is defective

Use the given values of n=1205 and p=0.98 to find the minimum value that is not significantly low, and the maximum value that is not significantly high.

C. Min-1171.18 Max: 1190.62

Which of the following is a biased estimator?

C. standard deviation

In recent year, 304 of the approximately 300,000,000 people in the US were struck by lightening. Estimate the probability that a randomly selected person in the US will be struck by lightening this year.

D. 0.00000101

The probability that a radish seed will germinate is 0.7. Estimate the probability that of 140 randomly selected seeds, exactly 100 will germinate

D. 0.0669

If z is a standard normal variable, find P(z>0.97)

D. 0.1660

A company manufactures batteries in batches of 6 and there is a 3% rate of defects. Find the mean number of defects per batch.

D. 0.2 defects

A banks loan officer rates applicants for credit. The ratings are normally distributed with a mean or 200 and a standard deviation of 50. If an applicant is randomly selected, find the probability of a rating that is between 200 and 275

D. 0.4332

Results from a marijuana drug test study showed 143 subjects with positive test results including 24 false positive results. There were 157 negative results, including 3 false negative results. What is the probability that a randomly selected subject did not use marijuana?

D. 0.593

The given values are discrete. Use the continuity correction and describe the region of the normal distribution that corresponds to the indicated probability.

D. The area to the left of 35.5

Determine whether the given procedure results in a binomial distribution. If not, state the reason why. • Rolling a single die 53 times, keeping track of the "fives" rolled.

D. The procedure results in a binomial distribution