The following frequency distribution presents a set of exam scores for a class of N= 20 students.

X F CF % C%
90-99 4 20 20 100
80-89 7 16 35 80
70-79 4 9 20 45
60-69 3 5 15 25
50-89 2 2 10 10
a)Using interpolation find the 30th percentile.

The answer I came up with was 72.




40th percentile


81st percentile

-Are my answers correct. I did the % portion of the table myself. I'm not sure if I did it correctly though.

Thank You

  1. 👍
  2. 👎
  3. 👁
  1. I realize the table looks off. X= the scores 93-95...etc. cf= 4,7,4,3,2,. %=20,35,20,15,10. c%=100,80,45,25,10.

    1. 👍
    2. 👎

Respond to this Question

First Name

Your Response

Similar Questions

  1. basic statistics for the behavioral sciences

    (a)on a normal distribution of exam scored, poindexter scored at the 10th percentile, so he claims that he outperformed 90% of his class. Why is he correct or incorrect? Because Foofy's score is in a tail of the distribution, she

  2. Business

    In a frequency distribution, what is the number of observations in a class called? A. class midpoint B. class interval C. class array D. class frequency E. none of the above

  3. statistics

    Scores from a statistics exam are reported as deviation scores. Which of the following deviation scores indicates a higher position in the class distribution?

  4. statistics

    The data represents the daily rainfall (in inches) for one month. Construct a frequency distribution beginning with a lower class limit of 0.00 and use a class width of 0.20. The frequency of the first class limit (0.00 – 0.19)

  1. Science

    _[blank]_ show the distribution and frequency for a set of values. _[blank]_ is how the values are spread out or grouped, and _[blank]_ is how often a value occurs in a set of numbers. Histograms; distribution; frequency Scatter

  2. stats need help

    If all the values in a data set are converted to z-scores, the shape of the distribution of the z-scores will not be the same as the distribution of the original data. True or False?

  3. statistics

    1. The exam scores for the students in an introductory statistics class are as follows. 88 63 90 64 82 98 96 75 89 86 76 84 70 67 34 89 85 39 81 96 92 85 a. Compute the mean and the median score. b. Identify the shape of the

  4. Statistics... I need help

    . Assume that a set of test scores is normally distributed with a mean of 100 and a standard deviation of 20. Use the 68-95-99.7 rule to find the following quantities: (Hint: Make a drawing and label first) a. Percentage of scores

  1. Statistics

    In Professor Smith's statistics course, the correlation between students' total scores before the final exam and their final exam scores is r = 0.67. The pre-exam totals for all students in the course have a mean of 275 and a

  2. Statistics

    A recent survey determined the IQ score of a random selection of residents of Alaska. The accompanying relative frequency distribution table summarizes the results. Identify the class width for the given relative frequency

  3. eced

    A correlatibas .82 was found betweenen number of hours studied and final exam scores. A.students who stuief less received a high exam scores. B.students who studied who studied received lower exam scores. C.studying caused studies

  4. Math-statistics

    Assume that a set of test scores is normally distributed with a mean of 100 and a standard deviation of 20. Use the 68-95-99.7 rule to find the following quantiles: a.percentage of scores less than 100 b. relative frequency of

You can view more similar questions or ask a new question.