Test 5/6

A researcher determines that students are active about 60 += 12 (M += SD) minutes per day. Assuming these data are normally distributed l, what is the z score for students being active 48 minutes a week?

-1.00

What is the z score for scores in the bottom (below the mean) 2.5%

-1.96

A therapist goes through her records and finds that 200 of her 400 patients showed significant improvement in mental health over the past year. Hence, the probability of her patients showing significant improvement in mental health is_____.

0.50

The standard normal distribution is normally distributed with a mean of ____ and a variance of ____.

0;1

A researcher determines that students study an average 80 += 20 (M += SD) minutes per week. Assuming these data are normally distributed, what is the z score for students studying 100 minutes per week?

1.00

What is the z score for scores in the top (above the mean 2.5%?

1.96

A new poll showed that voters had no preference for either of three candidates. In this example, the probability of a vote for, say, candidate A equals _____.

1/3

State which area is bigger or if the two areas are equal: area A = the area to the right of the mean or area B = the area between z =+ 1.00

Area B is bigger

According to the ________ a sampling distribution will approach a normal distribution as the number of samples from a population increases.

Central limit theorem

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

Exactly equal to 0

normal distribution, 50% of all data _____.

Fall above the mean, fall below the median, fall above and below the mode

Samples are used for which of the following?

Generalize results to the population Learn more about populations Estimate population mean and standard deviation

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

Normal curve, normal distribution, Bell-shapes curve

The proportion or fraction of times an outcome is likely to occur is referred to as____.

Probability

What information can you get from the z score table?

Probability of a score

What information do you need to convert a raw score into a z score?

Raw score, sample mean, sample standard deviation

______ is the extent to which sample means of samples selected from the same population differ from one another.

Sampling error

The mean variance in a sample distribution of means is called ______.

Standard error of the meaning

The formula used to convert any normal distribution to a standard normal distribution with a mean of 0 and a standard deviation of 1.00 is called ______.

Standard normal transformation

Scores far form the mean are located in the _____ of a normal distribution.

Tails

By definition, the probability of an outcome or event is ______.

The proportion of times an outcome is likely to occur The fraction of times an outcome is likely to occur Particularly useful for predicting the likelihood of random events

State which area is bigger, or if the two areas are equal: area A = the area to the left of z = 0.80, or area B = the area to the right of z = -0.80

The two areas are the same

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.

The normal distribution is symmetrical, which means that ____.

scores above the mean are distributed the same as scores below the mean

What is the implication for the tails of a normal distribution being asymptotic?

that extreme scores are possible in a normal distribution