Statistics of Frequency Distributions

The lengths of rivers in a state are given adjacent.

The mean river length is

• 556.25 kms

• 580.15 kms

• 602.40 kms

• 830. 830.56 kms

Which answer incorrectly describe the graph?

• Both distributions have equal mean

• Both distributions have equal mode

• Both distributions have equal median

•  Both distributions have equal standard deviation

The stem and leaf plot below shows the number of books bought by students in one book festival. Which of the following statements are true?        I. The range is 59.
 II. The median is 38.5.
III. The mean is 37.

• I only 

• II only 

• III only 

• I and II 

Which of the following statements are true?  
 I. Mode identifies the location of the peak in the frequency distribution graph
II. There can be more than one mode but no mode is impossible
III. Changing value of any score will change the mean
 IV. The symbol of median is ∑

• I and II

• II and IV

• I and III 

• III and IV

What is the expected count of a female who likes Pepsi?

• 10.5

• 11

• 14.5

• 6.3

Does the data give evidence of an association between gender and soft drink choice?

• Yes, we reject the null hypothesis.

• No, we fail to reject the null hypothesis

• No, we reject the null hypothesis.

• Yes, we fail to reject the null hypothesis.

• Cannot be determined because the large counts condition is not met.

The degrees of freedom for the chi-square test for this two-way table are

• 4

• 8

• 10

• 20

• 4876

The appropriate null hypothesis for performing a chi-square test is that

• equal proportions of female and male teenagers are almost certain they will be married in 10 years.

• there is no difference between the distributions of female and male teenagers' opinions about marriage in this sample.

• there is no difference between the distributions of female and male teenagers' opinions about marriage in the population.

• there is no association between gender and opinion about marriage in the sample.

• there is no association between gender and opinion about marriage in the population.

When we use grouped frequencies to display our data - we can use Ross or Hinkle conventions. Which statement is INCORRECT?

• The Ross convention is left end inclusive only

• The Hinkle convention uses an explicit midpoint

• The Ross convention will result in a loss of precision due to the width of class interval

• The Hinkle convention is right end inclusive only

Which statement is CORRECT while considering your class interval?

• A too narrow class interval can result in a loss of precision

• A too wide class interval can result in a loss of distribution pattern

• A too narrow class interval can result in sparse data collection

• A too wide class interval can result in empty intervals