Question

1. It is useful to know how spread out the scores are. Which one of the following is not a measure of "spread" among the scores?

variance

standard deviation

mean

range

2. Which descriptive statistic would depend directly on the sample size (number of data points) in the calculation process?

Standard deviation

Median

Range

Mode

3. To gather feedback on a new iPhone app, users are asked to rate the app on a scale of 1 to 5 in terms of "ease of use", with 1 being very difficult to use and 5 being very easy to use. The feedback data from this single question would be considered a(n) ____ variable.

predictor

nominal

ordinal

equal-interval

4. When calculating the variance of a group of numbers, the difference between each data point and the mean needs to be squared. What is the rationale behind this step?

Squaring the difference between a data point and the mean is the way to calculate distance.

The difference between each data point and the mean is the standard deviation.

To make sure all the numbers are positive and won't cancel each other out when the differences are added up.

To make the differences between the data points and the mean larger and easier to handle.

Answer #1

1) We know that the measures of spread describe how similar or varied the set of some observed values are for any particular data item. If we summarize any dataset then it would be helpful for us to understand the data when the dataset is large. The mean, median and mode can summarize the dataset into a single value that can represent all values in the dataset but it does not display the full scenario. On the other hand, with the help of measures of spread we can summarize the data in a way that shows how scattered the values are and how much they differ from the mean value. Thus, we know, that the measures of spread include the range, quartiles and the interquartile range, variance and standard deviation.

Thus, from the above discussion we summarize that among the given four options "mean" is not a measure of spread.

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112
97 .
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0.5
1.1
2.12
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Treatment A
Treatment B
Treatment C
13
17
15
13
15
13
14
15
18
16
13
18
F-ratio = _______________
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2)
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3)
0.4379
4)
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5)
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