For 100 randomly selected recent (past 5 years) college graduates, the following yearly income (in thousands of dollars) frequency distribution was obtained.

Class LimitsFrequency

0 -928

10 - 1930

20 - 2925

30 - 3912

40 - 495

Using the frequency distribution provided above, find the following:

a)Meanb)Modal Class

c)Sample Varianced) Sample Standard Deviation

Another Question:

In Minnesota, K-12 substitute teachers who work whenever asked earn an average yearly

salary of $6,000 for teaching.If the distribution of salaries is approximately normal with

a standard deviation of $1,000, what is the probability that a randomly selected K-12

substitute teachers makes the following:

a)More than $9,000 a year.b)Between $3,000 and $5,000 a year.

Question 3:

10.Nationwide, the mean ACT score is 21.4.A survey of 25 Ohio scores showed a mean

of 20.8.If the standard deviation for the sample is 3, can we conclude that Ohio is

below the national average?Use the five-step testing method with = .05.