statistics

posted by .

a mean score on a standardized test is 50 with a standard deviation of 10. What are the following:

1. what scores fall between -1 and +1 standard deviation?

2. what percent of all scores fall between -1 and +1 standard deviation?

3. what score falls at +2 standard deviations?

4. What percentage of scores falls between +1 and +2 standard deviations?

  • statistics -

    Z score is your score in terms of standard deviations.

    Z = (score-mean)/SD

    For the percentages, find table in the back of your statistics text labeled something like "areas under normal distribution" to find the proportion related to the Z score. Multiply by 100 for the percentage.

Respond to this Question

First Name
School Subject
Your Answer

Similar Questions

  1. Stastics

    When we convert x-value to z- score and use Standard Normal distribution, which of the following statements is true?
  2. Statistics

    Suppose that a sample of 50 scores has a mean of Y=90 and the standard deviation is 15. Between what two values of Y will at least 90% of the scores fall?
  3. Statistics

    The distribution of scores on a test is mound-shaped and symmetric with a mean score of 78. If 68% of the scores fall between 72 and 84, which of the following is most likely to be the standard deviation of the distribution?
  4. MATH

    A mean score on a standardized test is 50 with a standard deviation of 10. Answer the following a. What scores fall between –1 and +1 standard deviation?
  5. statistics

    2. Why is it important to know the mean and standard deviation for a data set when applying the empirical rule?
  6. statistics

    A standardized third grade reading test, called the We Can Read Test, has a mean of 50 with a standard deviation of 10. A developmental psychologist conducts a study, where he assesses the reading ability of a random sample of 75 third …
  7. Statistics

    The distribution of IQ scores is a nonstandard normal distribution with a mean of 100 and a standard deviation of 15. What are the value of the mean and standard deviation after all IQ score have been standardized by converting them …
  8. Foundations of Measurement

    Approximately 400,000 students took the GRE in 2009. Observed mean for the Verbal score was 540 with a standard deviation of 80, and the observed mean quantitative score was 500 with a standard deviation of 100. Assuming distribution …
  9. statistics

    1. Suppose you administered an anxiety test to a large sample of people and obtained normally distributed scores with a mean of 45 and a standard deviation of 4. Do not use the web calculator to answer the following questions. Instead, …
  10. Algebra

    I do not understand this homework at all. Any help or elaboration would be greatly appreciated. Thanks. 100 juniors at Southwest High took the SAT test. The scores were distributed normally with a mean of 22 and a standard deviation …

More Similar Questions