Data analysis

A researcher determines that students are active about 60 ± 12 ( M ± SD) min/day. Assuming these data are normally distributed, what is the z score for students being active 48 min/week?

-1.0

A researcher finds that 20 of 120 students failed an exam. In this case, the probability of failing this exam was ______.

.17

A researcher records the following body mass index (BMI) scores for a group of participants: 28.4 ± 1.6 ( M ± SD). Participants who score between 25 and 30 on this scale are categorized as overweight. What percentage of participants fell in this overweight category?

.8247

A researcher determines the probability that a research study will reveal something new is p = .80. What is the probability that the study will reveal something new or not reveal something new?

1.00

If there are 13 heart cards in a deck of 52 cards, then what is the probability of selecting one heart card on a single draw from the deck of cards?

13/52

A researcher reports that the probability of a college student living on campus is p = .38. If a small local college has 2,000 students enrolled, then what is the standard deviation of college students living on campus? Hint: This is a binomial probability distribution.

21.7 students

A professor records the following final exam scores: 78 ± 7 ( M ± SD). Students scoring in the top 14% get an A. What is the cutoff score for the top 14% in this example?

85.56

Which of the following is a mathematical formula that relates the conditional and marginal (unconditional) probabilities of two conditional outcomes that occur at random?

Bayes's theorem

A theoretical distribution that evenly distributes data around the mean, median, and mode is called the

all of these

Fractiles are ways that data can be divided into two or more equal parts. An example of a fractile includes

all of these

The range, a measure of variability,

all of these

Which of the following is consistent with the empirical rule?

all of these

A distribution of probabilities for random outcomes of a bivariate or dichotomous random variable is called a

binomial probability distribution

A researcher records the number of buckets of popcorn purchased by patrons during one night at the movies. She finds that the probability that a patron purchased 0 buckets of popcorn is p = .27; 1 bucket is p = .51; 2 buckets is p = .17; and 3 buckets is p = .05. How many buckets of popcorn can we expect a patron to purchase per night at the movies in the long run?

exactly 1 bucket of popcorn per night

A researcher finds that the average preschool-aged child drinks two cups of milk per day. Assuming these data are normally distributed, the z score for the average cups per day in this example is

exactly equal to 0

The advantage of squaring the deviation of each score from the mean and then summing is that

it produces a minimal positive solution that is not zero, as long as all scores are not exactly the same value.

The following distribution most closely approximates a

normal distribution

The ______ are the range of continuous values containing the score of interest in a binomial distribution.

real limits

A researcher records the following scores for attention during a video game task for two samples. Which sample has the largest standard deviation?Sample A: 10, 12, 14, 16, and 18Sample B: 20, 24, 28, 32, and 36

sample b

A main disadvantage of computing a range is that it takes into consideration only two values regardless of the number of scores in a distribution.

true

In a normal distribution with 3 ± 1 ( M ± SD), a researcher can appropriately conclude that about 84.13% of scores were greater than 2.

true

In a normal distribution, the probability of a score above -1.0 SD is equal to the probability of a score below +1.0 SD.

true

Mathematical expectation can be used to estimate the expected value of variance and standard deviation.

true

Probability distributions display the probability of each possible outcome for a given random variable.

true

The binomial probability distribution is distributed with u=np and o=(square root of npq)

true

The expected value of a random variable is the mean of a probability distribution.

true

The mean, median, and mode are all located at the 50th percentile in a standard normal distribution.

true

Regardless of the number of scores in a distribution, the range only includes ______ score(s) in its calculation.

two

Suppose you open a new game at the county fair. When patrons win, you pay them $3.00; when patrons lose, they pay you $1.00. If the probability of a patron winning is p = .20, then how much can you expect to win (or lose) in the long run? Hint: You need to compute the expected value of the mean.

win 0.20 cents per play

A therapist has a goal to reduce the mean number of patient symptoms expressed for a particular disorder to two symptoms per day. Following therapy, she determines that the z score for 2 symptoms per day is 0. Assuming the data are normally distributed, did she reach her goal?

yes, because a z score of 0 is the average, or mean

Multiplying or dividing each score using the same constant will not change the standard deviation.

false

Probability distributions follow the same rules as probability: They are never negative and vary between -∞ and +∞.

false

The closer a z score is to 0, the smaller the area is under the normal curve toward the tails.

false

The first step to locating proportions in a normal distribution is to first look up probabilities in the unit normal table.

false

The standard deviation and the mean can equal 0 in a data set that is normally distributed.

false

A binomial probability distribution is constructed for random variables that have at least two possible outcomes.

false

In a normal distribution, a score of 8 will always be more probable than a score of 0.

false