saint_zhu

Statistical concept

zeraeh

看答案，谢谢LZ

gracesun

thanks a lot

jacky_z

thanks

mayanfang1

Q9-10答案和详解如下：

Q9. Given the following frequency distribution:

Interval                    Frequency

10 up to 30            5

30 up to 50            10

50 up to 70            15

70 up to 90            5

 Which of the following statements is least accurate?

A)   The relative frequency of the second interval is less than 15.

B)   The absolute frequency of the third interval is 15.

C)   The number of observations is greater than 30.

Correct answer is A)

The relative interval frequency is (interval frequency) / (total number) = 28.57. The number of observations is 5 + 10 + 15 + 5 = 35.

Q10. Use the results from the following survey of 500 firms to answer the question.

 Number of Employees     Frequency

300 up to 400              40

400 up to 500              62

500 up to 600              78

600 up to 700              101

700 up to 800              131

800 up to 900                  88

The number of classes in this frequency table is:

A)     600.

B)     5.

C)     6.

Correct answer is C)

300 - 400 = 1, 400 - 500 = 2, 500 - 600 = 3, 600 - 700 = 4, 700 - 800 = 5, 800 - 900 = 6, Total = 6

mayanfang1

请看下一帖Q9-10的答案

mayanfang1

Q7-8答案和详解如下：

Q7. Use the results from the following survey of 500 firms to answer the question.

Number of Employees   Frequency

300 up to 400            40

400 up to 500                62

500 up to 600                78

600 up to 700              101

700 up to 800                131

800 up to 900                88

The cumulative relative frequency of the second interval (400 to 500) is:

A)   12.4%.

B)   20.4%.

C)   10.2%.

Correct answer is B)

62 + 40 = 102, 102 / 500 = 0.204 or 20.4%

Q8. Which of the following best describes a frequency distribution? A frequency distribution is a grouping of:

A)   selected data into intervals (classes) so that the number of observations in each of the non-overlapping intervals (classes) can be seen and tallied.

B)   independent intervals (classes) so that they can be seen and tallied.

C)   data into intervals (classes) so that the number of observations in each of the non-overlapping intervals (classes) can be seen and tallied.

Correct answer is C)

A frequency distribution is a tabular presentation of statistical data that aids the analysis of large data sets.