The frequency distribution below shows the distribution for IQ scores for a rand
ID: 3181057 • Letter: T
Question
The frequency distribution below shows the distribution for IQ scores for a random sample of
1000 adults. (Show all work. Just the answer, without supporting work, will receive no credit.)
IQ Scores
Frequency
Cumulative Relative Frequency
50 - 69
23
70 - 89
249
90 -109
0.743
110 - 129
130 - 149
25
Total
1000
(a)Complete the frequency table with frequency and cumulative relative frequency. Express the cumulative relative frequency to three decimal places.
(b)What percentage of the adults in this sample has an IQ score between 90 and 129, inclusive? (c) Which of the following IQ score groups does the median of this distribution belong to? 70 – 89, 90 – 109, or 110 – 129? Why?
IQ Scores
Frequency
Cumulative Relative Frequency
50 - 69
23
70 - 89
249
90 -109
0.743
110 - 129
130 - 149
25
Total
1000
Explanation / Answer
(a)
Following is the completed table:
(b)
The percentage of the adults in this sample has an IQ score between 90 and 129, inclusive is
0.975 - 0.272 = 0.703 =70.3%
(c)
Median is data value that has 50% scores less than from it. So median lie in the class 90-109.
IQ Scores Frequency Cumulative Relative Frequency Cumulative frequency 50-69 23 23/1000=0.023 23 70-89 249 272/1000=0.272 272 90-109 743-(249+23)=471 0.743 0.743*1000=743 110-129 232 0.975 743+232=975 130-149 25 1 1000 Total 1000Related Questions
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