Chapter 3 Cumulative Test Sample 30 people spent on books ($)

1) qualitative or quantitative and level of measurement Data is quantitative Data is ratio (there is a true 0)

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.

3. Make frequency distribution with 5 classes. Include class limits, midpoints, frequencies, boundaries, relative freq and cumulative freq.

Frequency histogram and polygon

Stem and leaf 9 : : : : : : 15 : : : : : 15

Box and whisker (boxplot)

Mean median and mode Mean= $ Median= $ Mode = $ These are statistics because they describe a sample

Range, variance and standard deviation Range = $ = $105 Variance = standard deviation = $32.26 The range is larger than 3 standard deviations.

Probability spending < $120 Frequency estimate = 14/30=.467 Prob randomly selecting person who spent more than $120. There are 15 such people in the sample. So Prob=0.5

Prob person spent $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

5 person sample. Prob (at least one spent > $175) Pr(any person spent > $175) = 5/30 =.1667 Pr(at least 1 person spent > $175) = 1 - Pr(no people spent > $175) Assume samples are independent (i.e not from the 30 people sampled, which would be a dependent sample Pr(one person > $175) =.8333 Pr(1 or more) = ^5 =.598 If dependent then = *24*23*22*21/(30*29*28*27*26) =.627

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