Relative Frequencies for Comparisons.Construct the relative frequencies and answer the given questions.

White Blood Cell Counts Construct one table (similar to Table) that includes relative frequencies based on the frequency distributions from Exercises 1 and 2, and then compare the white blood cell counts of females and males. Are there notable differences?

Table

IQ Scores from the Low Lead Group and the High Lead Group

Exercise

Exercise 1

identify the class width, class midpoints, and class boundaries for the given frequency distribution. The frequency distributions are based on real data from Appendix B.

Exercise 2

identify the class width, class midpoints, and class boundaries for the given frequency distribution. The frequency distributions are based on real data from Appendix B.

Answer :

Step 1 of 2 :

Given, White blood cell count of males and the frequency

White blood cell count of males |
Frequency |

3 - 4.9 |
8 |

5 - 6.9 |
15 |

7 - 8.9 |
11 |

9 - 10.9 |
5 |

11 - 12.9 |
1 |

We have to find the relative frequency for comparison

The total frequency = 82

Relative frequency =

Example :

Relative frequency =

= 20

class width : the difference between the upper and lower class limit.

Example : 4.9 - 3

= 1.9

class midpoints : (lower class limit + upper class limit)/ 2

Example : (3+4.9)/2

= 3.95

class boundaries :

Upper class boundary = Upper limit + () unit of measurement

Ex: 4.9 is the upper class limit and unit of measurement is 0.1

Therefore ,

Upper class boundary = 4.9 + () 0.1

= 4.95

Lower class boundary = Lower limit + () unit of measurement

Ex: 4.9 is the upper class limit and unit of measurement is 0.1

Therefore ,

Upper class boundary = 3 + () 0.1

= 3.05

White blood cell count of males |
Frequency |
Relative frequency |
Class width |
Class midpoints |
Class boundaries |

3 - 4.9 |
8 |
20 |
1.9 |
3.95 |
(3.05 , 4.95) |

5 - 6.9 |
15 |
37.5 |
1.9 |
5.95 |
(5.05 , 6.95) |

7 - 8.9 |
11 |
27.5 |
1.9 |
7.95 |
(7.05 , 8.95) |

9 - 10.9 |
5 |
12.5 |
1.9 |
9.95 |
(9.05 , 10.95) |

11 - 12.9 |
1 |
2.5 |
1.9 |
11.95 |
(11.05 , 12.95) |