FiltersDone

Question type

Essay

Multiple Choice

Short Answer

True False

Matching

Exam 4: Summarizing Data: Variability

Show Answer

Share

---

All types

Filters

Study FlashcardsPractice ExamLearn

Question 41

True/False

Review LaterAdd Note

Review Later

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

Correct Answer

verified

Show Answer

Question 42

Multiple Choice

Review LaterAdd Note

Review Later

A researcher selects a sample of 24 participants and has them complete a survey on dating preferences.In this example,what are the degrees of freedom for sample variance and what does this figure represent?

A) df = 24;it represents the number of scores that are free to vary in a sample.
B) df = 23;it represents the number of scores that are free to vary in a sample.
C) df = 23;dividing SS by df makes the sample variance a biased estimator of the population variance.
D) df = 24;dividing SS by df makes the sample variance an unbiased estimator of the population variance.

Correct Answer

verified

Show Answer

Question 43

True/False

Review LaterAdd Note

Suppose a researcher observes a population of 12 people and computes SS = 192.In this example,the standard deviation is 4.

Measures of variability can range in value from

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

The sum of the squared deviations of scores from their mean

A main disadvantage of computing a range is that it is a simple and quick measure of variability.

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

A researcher decides to split scores on an exam into quartiles.She determines that a score of 64 is at the 25th percentile,a score of 74 is at the 50th percentile,and a score of 80 is at the 75th percentile.What is the interquartile range (IQR) for these data?

A researcher computes the computational formula for SS,as finds that ∑x = 39 and ∑x² = 271.If this is a sample of 6 scores,then what would SS equal using the definitional formula?

The range,a measure of variability,

A researcher computes the computational formula for SS,as finds that ∑x = 22 and ∑x² = 126.If this is a sample of 4 scores,then what would SS equal using the definitional formula?

On average,the sample variance equals the population variance only when dividing SS by df.

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 3 instruments at the 25th percentile,5 instruments at the 50th percentile,and 8 instruments at the 75th percentile.What are the IQR and SIQR for these data?

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?

An interquartile range removes

The computational formula for the variance requires that you know the value of the mean.

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

The sample standard deviation is equal to 6 when SS = 360 and n = 11.

A researcher records the time in seconds it takes a sample of participants to walk alone through a dark portion of campus.The researcher computes SS = 1,200.Assuming that a sample of 25 participants was observed in this study,what is the standard deviation for these data?