Practice Test Answers

How might the graph be misleading?

Vladimir rolls a six-sided number cube 36 times. If getting a 3 is a success, what is the probability of a success?

The life spans of a computer manufacturer’s hard drives are normally distributed, with a mean of 3 years 6 months and a standard deviation of 9 months. What is the probability of a randomly selected hard drive from the company lasting between 2 years 3 months and 3 years 3 months? Use the portion of the standard normal table to help answer the question. z Probability 0 point 0 0 0 point 5 0 0 0 0 point 2 3 0 point 5 9 1 0 0 point 3 3 0 point 6 2 9 3 0 point 6 7 0 point 7 4 8 6 1 point 0 0 0 point 8 4 1 3 1 point 3 3 0 point 9 0 8 2 1 point 6 7 0 point 9 5 2 5 2 point 0 0 0 point 9 7 7 2

The grades of a science test are normally distributed. Thanh finds that his grade on the test has a z -score of negative 2 point 5 Which statement must be true?

A normal distribution of data has a mean of 90 and a standard deviation of 18 What is the approximate z -score for the value 64 ?

The president of the math club is conducting a survey to see where the twelfth-grade class wants to go on their field trip. Instead of asking the whole class, she surveys only the twelfth-grade members of the math club. She records their choices and plans to present the results to the school principal. What type of sampling did she use?

Laila guesses on all 20 questions of a multiple-choice test. Each question has 4 answer choices. What is the probability of a success and a failure for this experiment?

When finding the margin of error for the mean of a normally distributed population from a sample, what is alpha , assuming a confidence level of 74 percent ?

Which set of population data is the least dispersed from its mean?

Veronique has a spinner with three sections of equal size, red r , green g , and blue b The spinner is spun twice. The sample space for the possible outcomes is cap s is equal to rr, rb, rg, gr, gg, gb, br, bg, bb If the number of times red is spun is the random variable, cap x , which graph represents the probability distribution?

The set of life spans of an appliance is normally distributed with a mean mu is equal to 48 months and a standard deviation sigma is equal to 8 months. What is the life span of an appliance that has a z -score of negative 3 ?

Weston completed a hypothesis test and found that he could not reject the null hypothesis. Which of the following is a valid reason for his conclusion?

Kavita has been assigned the task of studying the average customer receipt for a branch of a major restaurant chain. The average receipt for the chain is 72 point 0 0 dollars with a standard deviation of 11 point 0 0 dollars The branch she is studying has an average bill of 67 point 0 0 dollars for the last 40 receipts. She needs to know if this falls below the chain’s average. She will use a 1 percent level for significance because she does not want to inadvertently report the restaurants income as below average. Upper-Tail Values A 5 percent 2 point 5 percent ​1% Critical z -v alues 1 point 6 5 1 point 9 6 2 point 5 8 Which choice depicts the result for Kavita’s hypothesis test?

A utility company hires pollsters to knock on random doors in different parts of town to survey residents about the cost of their electric bill. Would this study be biased? Why or why not?

A company has an opportunity to bid on three contracts. Determine which would be the best investment given the information in the table. Probability of Profit and Loss by Contract Contract Profit, Probability of Profit Probability to Break Even Loss, Probability of Loss Southeast 45 dollars comma 000 , 50 percent 30 percent 6 dollars comma 000 , 20 percent Southwest 60 dollars comma 000 , 35 percent 40 percent 10 dollars comma 000 , 25 percent California 112 dollars comma 000 , 20 percent 40 percent 40 dollars comma 000 , 40 percent

Miguel Cabrera has had 369 at bats, and he has 127 hits and 21 home runs. (Note: The home runs are included in the hits data.) If he is challenged to a batting battle, what is the expected score of each at bat if he earns 1 point for each hit that is not a home run and 5 points for each home run?

Opal is collecting data on water levels in different parts of town. She notices that her sample data has a low-value outlier. Which statement must be true?

Which is an accurate comparison?

A local newspaper compiles data on the number of days, cap x , people in a neighborhood receive the newspaper. The probability distribution for the data is shown in the table. What is the probability that a randomly chosen person receives the newspaper at least one day per week?

The distribution of the values of a population is shown in the graph, and a simple random sample is drawn from the population. Based on this information alone, can the sample be used to make inferences about the population?