Introductory statistics questions.

In computing descriptive statistics from grouped data,

1. Data values are treated as if they occur at the mid point of a class
2. The grouped data result is more accurate than the ungrouped result
3. The gropued data computations are used only when a population is being analyzed
4. None of these alternatives is correct

The measure of dispersion that is influenced most by extreme values is

1. The variance
2. The standard deviation
3. The range
4. The interquartile range

When should measures of location and dispersion be  computed from grouped data rather than from individual data values?

1. As much as possible since computations are easier
2. Only when individual data values are unavailable
3. Whenever computer packages for descriptive statistics  are unavailable
4. Only when the data are from a population.

The descriptive measure of dispersion that is based on the concept of a deviation about the mean is

1. The range
2. The interquartile range
3. The absolute value of the range
4. The standard deviation

The measure of loaction which is the most likely to be influenced by extreme values in the data set is

1. Mean
2. Median
3. Mode
4. Variance

The most important statistical descriptive measure of the location of a data set is the

1. Mean
2. Median
3. Mode
4. Variance

The numerical value of standard deviation can never be

1. Larger than the variance
2. Zero
3. Negative
4. Smaller than the variance

The sample variance

1. Is always smaller than the true value of the population variance
2. Is always larger than the true value of the population variance
3. Could be smaller, equal to, or larger than the true value of the population variance
4. Can never be zero