EBook Problems EDA Shape
Contents
EBook Problems Set - Measures of Shape
Problem 1
46% of the likely voters in Los Angeles intend to vote for Mayor James. Suppose we take a random sample of 1000 likely Los Angeles voters. For every person in our sample who intends to vote for Mayor James we will record a "1". For every person who will not vote for the mayor, we will record a "0". Suppose we now make a histogram of our results. Which of the following is a good description of the histogram?
- Choose one answer.
- (a) The distribution will have a spike at the value 0.46
- (b) The distribution will be approximately normal
- (c) The sample size is too small to tell
- (d) The distribution will show about 46% of the replies at 1 and 54% at 0
Problem 2
The Old Faithful Geiser in Yellowstone, Wyoming, erupts pretty regularly. After an eruption has occurred, one has to wait for the next eruption for some time. The waiting time has a histogram with two peaks or bumps (bimodal): one peak in the lower end and one in the upper end, with very little frequency in between. What does this suggest about the waiting time?
- Choose one answer.
- (a) The waiting time does not depends on how long the last eruption was
- (b) The waiting time should have been plotted with a bar graph, not a histogram
- (c) There are two groups of waiting times, and in order to study this variable, we should analyze each group separately
Problem 3
From what kinds of variables sould a histogram be generated?
- Choose one answer.
- (a) Quantitative only
- (b) Categorical only
- (c) Varies according to situation
- (d) One categorical and one quantitative
Problem 4
Imagine that students find a recent 10 point quiz very easy and almost all do very well. Describe the shape of distribution of scores when you plot the scores on this quiz.
- Choose one answer.
- (a) The distribution of scores is skewed left since some students did not do well.
- (b) The distribution of scores is bimodal since some students did well and some did not.
- (c) The distribution of scores is nearly normal since quiz grades are curved.
- (d) It is not possible to describe the shape of the distribution unless you have the actual values.
- (e) The distribution of scores is skewed right since some students did not do well.
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