Q SCI 381
Dr.Bare
Name:________________________
Hourly Examination One Answers
1. descriptive; census
2. ratio; quantitative; statistic
3. Class Frequency
3-5
4
6-8
3
9-11
4
12-14
4
Class limits of second class are 6 and 8, respectively.
Class width = 3
The histogram is based on class boundaries: 2.5-5.5; 5.5-8.5; 8.5-11.5; 11.5-14.5
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2.5
5.5
8.5 11.5 14.5
Uniform
0| 3 4
0| 5 5 6 7 8 9
1| 0 0 1 2 2 2 4
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4. sample mean = 8.53
sample standard deviation = 3.40
median = 9
First, find that 3.435 and 13.631 are –1.5 and 1.5 standard deviations below and
above the mean, respectively. Hence, k = 1.5. Then 1 – 1/k2 = 55.6%
Since the distribution is fairly uniform and symmetric it doesn’t matter too much
in this case. Note that the median is > the mean implying a slight left-skewed
distribution.
The IQR = Q3 – Q1 = 12 – 5 = 7
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3 5 7 9 10 11 12 13 14
5. stratified random sample;
ordinal and qualitative
systematic
ratio
true
experiment