Statistics, basic concepts

Which one of the following statements is false?

• The only way the standard deviation can be 0 is when all the observations have the same value.

• If you interchange the explanatory variable and the response variable, the correlation coefficient remains the same.

• If the correlation coefficient between two variables is 0, that means that there is no possible relationship between the two variables.

• The correlation coefficient has no units.

Consider the following data set: 2   3   5   7   8   10    12    15    20    29, according to the 1.5(IQR) rule,

• only 29 is an outlier

• only 2 is an outlier

• both 2 and 29 are outliers

• there are no outliers

A national random sample of 20 ACT scores from 2010 is listed below.

      29, 26, 13, 23, 23, 25, 17, 22, 17, 19, 12, 26, 30, 30, 18, 14, 12, 26, 17, 18.

      Calculate the sample mean and standard deviation. 

• 20.50 ,  5.79

• 20.50 ,  5.94

• 20.85 ,  5.79

• 20.85 ,  5.94

The histogram above represents the lifespan of a random sample of a particular  type of insect.

Determine the relationship between the mean and median.

• mean = median

• mean ≈ median

• mean < median

• mean > median

The data in the scatterplot below would have a correlation coefficient that is

       close to:

• –1.0

• –0.5

• +1.0

• +0.5

The five‐number summary of a distribution consists of

• mean, median, standard deviation, and two quartiles.

• minimum, maximum, mean, median, and standard deviation.

• minimum, maximum, median, and two quartiles

• mean, standard deviation, correlation, and two quartiles

In a class of 31 students, how many would be above the third quartile?

• 16

• 7

• 8

• 15

Mean. Median and Mode are equal in a

• Continuous

• unsymmetrical distribution

• symmetrical distribution

• None

Which measure of spread indicates variation about the mean?

• mean

• median

• mode

• Standard deviation

If the correlation coefficient is a positive value, then the slope of the regression line

• must also be positive

• can be either negative or positive

• can be zero

• can not be zero