1. Nausea from air sickness affects some travelers. A drug company, wanting to establish the effectiveness of its motion sickness pill, randomly gives either its pill or a look-alike sugar pill (placebo) to 200 passengers.
Complete the marginal totals.Round your answers to two decimal places.
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|
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Degree of Nausea
|
|
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None
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Slight
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Moderate
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Severe
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Total
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|
Pill
|
43
|
36
|
18
|
3
|
100
|
|
Placebo
|
19
|
33
|
36
|
12
|
100
|
|
Total
|
|
|
|
|
|
a. Complete the marginal totals
b. Calculate the relative frequencies separately for each row.
2. Breakfast cereals from three leading manufacturers ca be classified either above average or below average in sugar content, Data for ten cereals from each manufacturer are given below.
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Below Average
|
Above Average
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Total
|
|
General Mills
|
2
|
8
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10
|
|
Kelloggs
|
3
|
7
|
10
|
|
Quaker
|
4
|
6
|
10
|
|
Total
|
|
|
|
a. Complete the marginal totals
b. Calculate the relative frequencies separately for each row.
3. If the value of r is small, can we conclude that there is not a strong relationship between the two variables?
Calculations from a data set of n = 30 pairs of (x,y) values have provided the following results: sigma-summation Superscript ? Baseline left-parenthesis x minus x Overscript ¯ EndScripts right-parenthesis squared equals 530.7, sigma-summation Superscript ? Baseline left-parenthesis y minus y Overscript ¯ EndScripts right-parenthesis squared equals 215.2 , sigma-summation Superscript ? Baseline left-parenthesis x minus x Overscript ¯ EndScripts right-parenthesis left-parenthesis y minus y Overscript ¯ EndScripts right-parenthesis equals -207
Obtain the correlation coefficient. Round your answer to three decimal places.
4. A store manager has determined that the monthly profit y realized from selling a particular brand of car battery is given by
y = 11x - 155
where x denotes the number of these batteries sold in a month.
At least how many batteries must be sold in a month in order to make a profit? (Give a whole number.)