### Bio statistical Applications in Public Health – **Quiz 1** Ch 1,2,3

In chapter 1, 2 and 3 we discuss Bio-statistical applications in public health including Data Types, Center, Spread, Visualizations, and Probability.

Which level of measure describes teachers as rated as excellent, good, average, or poor?

ratio

**ordinal** **–** **Correct **

interval

nominal

ExplanationThe correct answer is ordinal. The data is measured in a hierarchical order (e.g. excellent is high, poor is low), but no numerical information can be obtained from these values.

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In some research, nominal data is quantitative.

True

**False –** **Correct**

——————–

You gathered a sample of nominal data (e.g. ethnicity). You’d like to obtain a value representing the center of your data set.

Which measure of central tendency should you use?

Mean

**Mode** **–** **Correct**

There is no measure of central tendency for nominal data.

Median

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Systolic Blood Pressure of Women | Frequency |

80-99 | 11 |

100-119 | 20 |

120-139 | 6 |

140-159 | 2 |

160-179 | 0 |

180-199 | 1 |

What is the relative frequency for the for the 80-99 class?

**27.5%** **–** **Correct!**

15.0%

05.5%

50.0%

——————–

What is the approximate frequency for the 21-30 class?

0

**100** **– Correct**

150

50

——————–

A scatter plot contains a numerical variable along the x-axis and a numerical variable along the y-axis.

**True –** **Correct!**

False

——————–

Which type of graph is depicted below

Which type of visualization is depicted above

pie chart

**pareto chart** **– Correct**

histogram

scatterplot

ExplanationThe graph depicted above is a Pareto chart. The most common mistake is to confuse the histogram with the praeto chart. The main difference between a histogram and a praeto chart is located in the x-axis. Within a histogram, the x-axis contains a numerical, quantitative variable (e.g. height, weight) whereas a praeto chart contains a categorical, qualitative variable (e.g. gender, ethnicity).

——————–

Which type of visualization is depicted above?

praeto charts

dot plot

**histogram – Correct**

pie chart

——————–

Which measure of central tendency is most accurate when you have outliers within your dataset?

**median** **–** **Correct**

midrange

mean

mode

——————–

The standard deviation calculations are identical for a sample data set and a population data set.

True

**False –** **Correct**

——————–

Calculate the mean (i.e. average) for the following data:

12, 14, 16, 18, 20

15

17

14

**16** **–** **Correct**

——————–

Calculate the median for the following data:

12, 14, 16, 16, 16, 18, 18, 20, 22, 24

16

18

**17** **–** **Correct**

19

——————–

Calculate the mode for the following data:

12, 12, 14, 14, 14, 15, 16, 16, 17, 18, 20

**14 –** **Correct**

15

16

12

——————–

Which distribution (top or bottom) likely has the larger standard deviation?

bottom

**top – Correct**

ExplanationRecall, the standard deviation describes the spread of the data. Therefore, the larger the standard deviation the more spread out the distribution is (i.e. the wider it will be, displayed in the top image). A smaller standard deviation will be associated with a less spread out distribution (i.e. a thinner distribution, like the bottom image).

Calculate the z-score for the following information:

Raw Score (X) = 12

Mean (X̄)= 14

Standard Deviation (s) = 1.5

1.24

2.79

-2.13

**-1.3333** **– Correct**

Explanationz = (X - X̄) / s z = (12 - 14) / 1.5 z = -2 / 1.5 = -1.3333

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When calculating **the probability of event A or event B**, we should use the multiplication rule.

True

**False – Correct**

ExplanationWhen calculating the probability of event AorB occurring, we use theaddition rule(see page 109).

——————–

When calculating **the probability of event A and event B occurring**, we should use the multiplication rule.

**True** **–** **Correct**

False

——————–

The probability of rain tomorrow is 1/3.

The probability of ice tomorrow is 1/8.

What is the probability of rain and ice tomorrow?

1/8

1/3

**1/24** **–** **Correct**

11/24

——————–

The probability of attending work, given that it is Saturday, is an example of a conditional probability.

**True** **–** **Correct**

False

——————–

In the U.S., there were 2,416,000 deaths and 700,100 of them were due to heart disease.

The cause-of-death rate for heart disease is approximately 0.2898.

**True** **–** **Correct**

False