Chapter%203%20Cumulative%20Test

1
Chapter 3 Cumulative Test

• Sample 30 people spent on books ()
• 156 150 109 98 136 170 178 195 110 191 187 119
  104 160 132 117 111 120 103 123 153 91 162 93
  118 127 90 181 110 116

2
1) qualitative or quantitative and level of
measurement

• Data is quantitative
• Data is ratio (there is a true 0)

3
2) Method of data collection. Sampling technique

• Use a survey
• Collect data using random sampling (randomly
  chosen people)
• If data were systematic or convenience the sample
  might not be representative of the amount people
  spent on boods.

4
3. Make frequency distribution with 5 classes.
Include class limits, midpoints, frequencies,
boundaries, relative freq and cumulative freq.
5
Frequency histogram and polygon
6
Stem and leaf

• 9 0138
• 10 349
• 11 0016789
• 12 037
• 13 26
• 14
• 15 036
• 16 02
• 17 08
• 18 17
• 19 15

7
Box and whisker (boxplot)
8
Mean median and mode

• Mean 133.67
• Median 121.50
• Mode 100.50
• These are statistics because they describe a
  sample

9
Range, variance and standard deviation

• Range 195 -90 105
• Variance 1040.5
• standard deviation 32.26
• The range is larger than 3 standard deviations.

10
Probability spending lt 120

• Frequency estimate 14/30 .467
• Prob randomly selecting person who spent more
  than 120. There are 15 such people in the
  sample. So Prob0.5

11
Prob person spent lt 120 or gt 160

• These are mutually exclusive events (person
  cannot do both). So the probability is the sum of
  the probabilities of individual events which is
  14/30 7/30 21/30 .7

12
5 person sample. Prob (at least one spent gt 175)

• Pr(any person spent gt 175) 5/30 .1667
• Pr(at least 1 person spent gt 175) 1 - Pr(no
  people spent gt 175)
• Assume samples are independent (i.e not from the
  30 people sampled, which would be a dependent
  sample
• Pr(one person gt 175) .8333
• Pr(1 or more) 1 - .8335 .598
• If dependent then 1 - 2524232221/(3029282
  726) .627

13
How many ways can 5 respondents be resampled from
30?

• Order is not important so it is number of
  combinations of 30 things taken 5 at a time
• This is 142506