STAT 250 Probability

posted by .

Final averages are typically approximately normally distributed with a mean of 66 and a standard deviation of 10.5. Your professor says that the top 5% of the class will receive an A; the next 15%, a B; the next 47%, a C; the next 22%, a D; and the bottom 11%, an F.
(a) What average must you exceed to obtain an A?

(b) What average must you exceed to receive a grade of C or better?

(c) What average must you obtain to pass the course? (You'll need a D or better.)

  • STAT 250 Probability -

    I will let you play with

    http://davidmlane.com/normal.html

    click on "value from an area" and enter
    mean: 66
    sd: 10.5
    click on below and enter .95 in area
    I get 83.275
    So 95% of the students will have a score of less than 83

    the next 15 % will get a B
    so 20 % will get either A or B
    and 80% will not get A or B

    click on below and enter .8 in area
    I got 74.835 or 75% to 83 will get you a B
    67% will get at least a C
    enter .67 in area to get 70.615

    I will let you continue

Respond to this Question

First Name
School Subject
Your Answer

Similar Questions

  1. Statistics 250

    Final averages are typically approximately normally distributed with a mean of 65 and a standard deviation of 8. Your professor says that the top 10% of the class will receive an A; the next 20%, a B; the next 41%, a C; the next 19%, …
  2. Statistic

    Final averages are typically approximately normally distributed with a mean of 78 and a standard deviation of 11. Your professor says that the top 6% of the class will receive an A; the next 24%, a B; the next 41%, a C; the next 18%, …
  3. STAT 250 Probability

    Final averages are typically approximately normally distributed with a mean of 66 and a standard deviation of 10.5. Your professor says that the top 5% of the class will receive an A; the next 15%, a B; the next 47%, a C; the next …
  4. Statisitics

    In a large section of a Chemistry class, the points for the final exam are normally distributed, with a mean of 72, and a variance of 81. Grades are to be assigned according to the following rule: the top 10% receive As, the next 20% …
  5. STAT

    The score on a test are normally distributed with a mean of 75 and a standard deviation of 6. If the professor wishes to give A’s to the top 4%, what would be the cutoff score be for A’s?
  6. statistics

    Professor Smith gave a final exam in her history class. The scores on the final exam are normally distributed with a mean of 75 and a standard deviation of 6. If Professor Smith wishes to give A’s to the top 4%, what would be the …
  7. STATS HELP

    Final averages are typically approximately normally distributed with a mean of 72 and a standard deviation of 12.5. Your professor says that the top 8% of the class will receive an A, the next 20% a B, the next 42% a C, the next 18% …
  8. Math

    In a large section of a statistics class, the points for the final exam are normally distributed, with a mean of 72 and a standard deviation of 9. Grades are to be assigned according to the following rule: The top 10% receive A's. …
  9. Math

    In a large section of a statistics class, the points for the final exam are normally distributed, with a mean of 72 and a standard deviation of 9. Grades are to be assigned according to the following rule: The top 10% receive A's. …
  10. Stats

    In a large section of a statistics class, the points for the final exam are normally distributed, with a mean of 72 and a standard deviation of 9. Grades are to be assigned according to the following rule: The top 10% receive A's. …

More Similar Questions