Statistics CH 4

What is the sample standard deviation for this data set? 3, 4, 2, 4, 7 - 1.87 - 20 - 2.8 - 5

1.87

What is the IQR for this data set? 6, 4, 6, 6, 1, 6, 3, 4 - cannot be calculated - 5 - 2.5 - 0.5

2.5

When data are negatively skewed, which measure of variability is most appropriate? - Median - Range (i.e., high and low scores) - Standard deviation - Quartiles (such as the interquartile range)

Quartiles (such as the interquartile range)

Which measure requires a degrees of freedom calculation? - Sample IQR - Population standard deviation - Sample variance - Population range

Sample variance

For a normal distribution, which measure of variability is most efficient (in the statistical sense)? - Quartiles (such as the interquartile range) - Standard deviation - Median - Range (i.e., high and low scores)

Standard deviation

What is the range for this data set? 5, 3, 7+, 1, 4 - 6 - 1 - cannot be calculated - 6+

cannot be calculated

One good use of the range is to... - help in calculations of the standard deviation. - identify missing values. - check for outliers. - separate groups of cases.

check for outliers.

A narrow distribution that is sharply pointed in the middle and that has many outliers is called... - negatively skewed. - platykurtic. - positively skewed. - leptokurtic.

leptokurtic.

Compared to a mesokurtic distribution, the peak of platykurtic distribution is... - generally bimodal. - skewed. - not as high. - narrower.

not as high.

Which measure of variation is LEAST sensitive to outliers? standard deviation all are the same range IQR

IQR

When open-ended scores are present in the data, which measure of variability is most appropriate? -Range (i.e., high and low scores) -Median -Standard deviation -Quartiles (such as the interquartile range)

Quartiles (such as the interquartile range)

Compared to a mesokurtic distribution, the tails of a leptokurtic distribution... - are shorter. - have fewer outliers. - are longer. - cannot be trimmed.

are longer

If the formula for the population standard deviation were used with sample data, then result would be... - identical. - too small. - impossible to calculate. - too big.

too small

When scores in a data set are very close to one another, then the variance... - must be based on n > 50. - cannot be calculated. - will be biased for samples. - will be close to 0.

will be close to 0.

If scores in a data set are very different from each other, then the standard deviation... - cannot be calculated. - will be biased for the sample. - will be low. - will be high.

will be high.

For a normal distribution, kurtosis is... - negative. - 1. - 0. - undefined.

0

What is the population variance for this data set? 4, 1, 6, 1 - 5 - cannot be calculated with n < 10 - 4.5 - 2.12

4.5

What is the range for this data set? 5, 1, 2, 6, 5 - 6 - 5 - 2 - cannot be calculated

5

Which measure of variation is most influenced by outliers? IQR range standard deviation variance

range