Statistics in a Modern World 800
Solutions to Exam 2
-
- 5 Number Summary: 8 (1st) 10 (between 7th & 8th) 11 (14th) 12
(between 20th & 21st) 14 (last)
- (ii) fairly symmetric
- (ii) mean about equal to median
-
- (ii) bar graph is best for two categorical variables (one piechart
wouldn't do; you'd need two)
- (iii) scatterplot displays two measurement variables
- (ii) correlation between IQ's and heights should be closest to 0
because we don't expect these to be related
-
- z = (294-266)/16 = 1.75; the percentage above 1.75 equals percentage
below -1.75, or 4%
- the shortest 2% have z = -2.05; observed value = 266 -2.05(16)=233.2
-
- predicted shoesize = -13 + .322(62) = 7
- direction is (i) positive because .322 > 0; anyway, taller heights are
associated with longer feet.
- take 100 billion times 175 divided by 35: answer is 500 billion
-
- (i) long-term trend (decrease) is most pronounced
- (iv) irregular cycle of increase then decrease from '91 to '95
-
- 5 is answered for you
- 2
- 1
- 6
- 4
- 7
- 3
-
- first column 10 and 10; second column 20 and 20
- first column 4.9 and 4.9; second column 2.5 and 2.5
- chi-square is 14.8
- yes: 14.8 > 3.84 means we have statistical evidence of a relationship
- (ii) in general, upperclassmen tend to live off campus
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