Q: For the NV group fusion times, what is the formula for identifying an outlier using the interquartile range (IQR)?

$$\text{Outlier} \u003e Q_3$ + 1.5 \times IQR or$$ $$\text{Outlier} \u003c Q_1$ - 1.5 \times IQR$$

Question 1

A newspaper posts an online survey asking, 'How often do you seek medical information online?' Of 1072 Internet users who chose to respond, 38% said 'frequently.' What is the main issue with this sampling method?

Accepted Answer

It is a voluntary response sample, which can lead to bias because only those interested choose to respond.

Question 2

Which level of measurement is most appropriate for the variable 'brand of toothpaste'?

Accepted Answer

Nominal

Question 3

The number of wheels on a vehicle is best described as which type of data?

Accepted Answer

Discrete, because the data can only take on specific values.

Question 4

Which level of measurement is most appropriate for the prison population of different countries?

Accepted Answer

Ratio

Question 5

Given the following frequencies for grades: A (4), B (12), C (13), D (5), F (3), what is the relative frequency (as a percentage) for grade B?

Accepted Answer

24%

Question 6

What does it mean for the findings of a statistical analysis to be statistically significant?

Accepted Answer

The likelihood of getting these results by chance is very small.

Question 7

You have age data for award-winning male and female actors. Which graph would best compare the two groups and why?

Accepted Answer

A side-by-side box plot, because it shows the distribution, center, and spread for both groups.

Question 8

Given the cell phone radiation emissions (in W/kg): 1.36, 1.37, 1.59, 1.38, 1.42, 1.07, 0.42, 1.14, 0.74, 0.43, 0.21, what is the mean emission? (Round to two decimal places)

Accepted Answer

$$\frac{1.36+1.37+1.59+1.38+1.42+1.07+0.42+1.14+0.74+0.43+0.21}{11} = 1.02$$

Question 9

For the cell phone radiation data above, what is the midrange?

Accepted Answer

$$\frac{0.21+1.59}{2} = 0.90$$

Question 10

Which measure of center would be most appropriate for the cell phone radiation data if there is a strong outlier present?

Accepted Answer

Median, because it is less affected by extreme values.

Question 11

A five-number summary consists of which values?

Accepted Answer

Minimum, Q1, Median, Q3, Maximum

Question 12

For the NV group fusion times, what is the formula for identifying an outlier using the interquartile range (IQR)?

Accepted Answer

$$	ext{Outlier} \u003e Q_3$ + 1.5 	imes IQR or$$ $$	ext{Outlier} \u003c Q_1$ - 1.5 	imes IQR$$

Question 13

If a frequency table has bins of width 10 for ages of award-winning actors, and the lowest age is 25, what would be the first bin interval?

Accepted Answer

25–34

Question 14

Which of the following best describes the difference between a histogram and a box plot?

Accepted Answer

A histogram shows the frequency distribution of data, while a box plot shows the five-number summary and outliers.

Question 15

Given the NV group fusion times, if $$Q_1 = 2.3$, Q_3$ = 8.4$$, what is the interquartile range (IQR)?

Accepted Answer

$$8.4 - 2.3 = 6.1$$

Question 16

If the standard deviation of a data set is calculated using the formula $$s = \sqrt{\frac{\sum (x_i - \bar{x})^2$}{n-1}}$$, what does $$n-1$$ represent?

Accepted Answer

Degrees of freedom for a sample

Question 17

A cell phone is considered safe if its radiation emission is less than or equal to 1.6 W/kg. If the mean emission of a sample is 1.02 W/kg, what can you conclude?

Accepted Answer

On average, the cell phones in the sample are below the safety threshold.

Question 18

Which of the following is NOT a reason to prefer the median over the mean as a measure of center?

Accepted Answer

The median is always equal to the mean.

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