Exam 4: Summarizing Data: Variability

A researcher reports that the time (in minutes)it takes children who are "picky eaters" to finish their vegetables is negatively skewed,with children finishing their vegetables in 4.2 ± 1.0 (M ± SD)min.Based on Chebyshev's Theorem,we can conclude that

A researcher records the following motor assessment scores for two samples of athletes.Which sample has the largest standard deviation? Sample A: 8,10,12,15,and 18 Sample B: 16,18,20,23,and 26

A researcher records a sample of 30 exam scores and finds that the population variance for these data is larger than the sample variance.Is this possible?

A researcher records the number of individual instruments identified by students listening to a piece of classical music.He splits the data into quartiles and reports that students correctly identified three instruments at the 25th percentile,five instruments at the 50th percentile,and eight instruments at the 75th percentile.What are the IQR and SIQR for these data?

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

The sample variance is computed by dividing SS by ______,whereas the population variance is computed by dividing SS by ______.

A researcher measures the amount of coffee consumed by college students while studying during the final exam week.In her study,she found that students drink 2.3 ± 0.8 (M ± SD)cups of coffee per study session.Assuming the data are normally distributed,which of the following is the most appropriate conclusion?

The empirical rule states that all scores will fall within 3 standard deviations of the mean.

Adding or subtracting the same constant to each score will not change the standard deviation.

A researcher computes the computational formula for SS and finds that and .If this is a sample of 4 scores,then what would SS equal using the computational formula?

A researcher records the following scores on a working memory quiz for two samples.Which sample has the largest standard deviation? Sample A: 2,3,4,5,6,7,and 8 Sample B: 4,5,6,7,8,9,and 10

Suppose a researcher selects a sample of 16 participants and computes SS = 60.In this example,the standard deviation is 4.

A researcher records the number of classroom interruptions during each of two class sessions.Which session has the largest standard deviation? Session A: 12,15,18,24,and 30 Session B: 8,10,12,16,and 20

Which of the following describes the definitional formula for variance?

A reason for squaring deviations to compute SS in the numerator includes which of the following?

When the sample variance is computed as SS divided by n,it will underestimate the population variance on average.

Which of the following is true about the computational formula for variance?

The definitional formula for variance is stated in terms of how variance is defined.

Each deviation in the numerator for variance is squared because

Which of the following is the best explanation for why the standard deviation is almost always reported with the mean?