Språkstatistik HT96:03

Class:   03
Date:    960904
Topic:   Exercise class 1

Exercise class 1

These exercises are supposed to be handed in on Monday September 9.

1. Compute the average of the numbers 1, 2, 3, 4, 5, 7, 9, 11, 13, 15.

2. Compute the median of the numbers mentioned in execise 1.

3. Compute the standard deviation of the numbers mentioned in exercise 1.

4. Would the normal curve be a good description for the numbers mentioned in exercise 1?

   The following data on the literacy of Chinese people is available:
   10% knows between 0 and 1000 different characters
   5% knows between 1000 and 2000 different characters
   10% knows between 2000 and 3000 different characters
   15% knows between 3000 and 4000 different characters
   20% knows between 4000 and 6000 different characters
   20% knows between 6000 and 10,000 different characters
   15% knows between 10,000 and 25,000 different characters
   5% knows between 25,000 and 50,000 different characters

5. Draw a histogram for this data.

6. Make an estimation of the percentage of Chinese people that know between 4000 and 5000 characters. Also estimate the number of Chinese people that know between 8000 and 12,000 characters.

   The results of a test are distributed according to the normal curve with an average of 270 and a standard deviation of 40.

7. What SD value corresponds with a score of 290? And what score corresponds with an SD of -3.5?

8. What is the probability that someone will get a score between 0 SD and +2 SD for this test?

9. What is the probability that someone will get a score between 250 and 310?

10. Compute the 99.9th percentile for this test.

Each exercise is worth 1 point.