Question

Adults who are being tested for dementia are asked to perform mental tasks such as listing as many animals as they can in one minute. Here are the numbers of animals listed in one minute by 24 normal (non-demented) adults.

1,2,3,5,5,6,7,7,9,10,10,10,11,11,11,11,13,13,14,15,15,18,18,19

(a) Which measures of central tendency do not exist for this data set? Choose all that apply.

Mean

Median

Mode

None of these measures

(b) Suppose that the measurement 19 (the largest measurement in the data set) were replaced by 40. Which measures of central tendency would be affected by the change? Choose all that apply.

Mean

Median

Mode

None of these measures

(c) Suppose that, starting with the original data set, the largest measurement were removed. Which measures of central tendency would be changed from those of the original data set? Choose all that apply.

Mean

Median

Mode

None of these measures

(d) Which of the following best describes the distribution of the original data? Choose only one.

Negatively skewed

Positively skewed

Roughly symmetrical

Answer 1

Answer a) None of these measures

Explanation: All measures such as mean, median and mode exists for this dataet.

Answer b) Mean

Answer c) Mean and Median

Answer d)

Mean Calculation

Mean = 10.1667

Median Calculation

The median is the middle number in a sorted list of numbers. So, to find the median, we need to place the numbers in value order and find the middle number.

Ordering the data from least to greatest, we get:

1   2   3   5   5   6   7   7   9   10   10   10   11   11   11   11   13   13   14   15   15   18   18   19   

Median = (10+11)/2

Median = 10.5

In this casen, Median = 10.5 > Mean = 10.1667, the distribution is negatively skewed