pls help me working out population mean & median  TOPIC_SOLVED

Standard deviation, mean, variance, z-scores, t-tests, etc.

pls help me working out population mean & median

Postby hoeny123 on Thu Nov 11, 2010 8:35 pm

An insurance company is interested in a statistical profile of the age its clients in a particular geographic region. They provide you with grouped data on all (i.e. the population) of their clients in that region

Age Number

Less than 25 years old 20
25 years old to 34.99 years old 40
35 years old to 49.99 years old 50
50 years old to 64.99 years old 50
65 plus years old 30

Required

1. Calculate the mean age of the company’s clients in this region
2. Calculate the median age of the company’s clients in this region
3. Calculate the variance and standard deviation of the clients’ age in this region
4. Calculate the 25th and 75th percentile of the clients’ age.

please note that the class interval is unequal.

an early assistance would be very much appreciated....
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Postby stapel_eliz on Fri Nov 12, 2010 3:13 pm

hoeny123 wrote:An insurance company is interested in a statistical profile of the age its clients in a particular geographic region. They provide you with grouped data on all (i.e. the population) of their clients in that region

. . . . . . . . .Age. . . . . . . . . . . . . Number

Less than 25 years old. . . . . . . . . . ..20
25 years old to 34.99 years old. . . . ..40
35 years old to 49.99 years old. . . . ..50
50 years old to 64.99 years old. . . . ..50
65 plus years old. . . . . . . . . . . . . ...30

What is the midpoint value of each interval? (This value is, to my knowledge, necessary for the computations. Check your book for what assumptions you would make for the open-ended "65+" category.)

What is the total number of data points?

hoeny123 wrote:1. Calculate the mean age of the company’s clients in this region

Multiply each interval's midpoint value by that interval's number of data points. Sum the products. Divide by the total number of data points.

hoeny123 wrote:2. Calculate the median age of the company’s clients in this region

Divide the total number of data points by 2 to find the place of the median value. Find the interval which contains this place. The midpoint value is the median.

hoeny123 wrote:3. Calculate the variance and standard deviation of the clients’ age in this region

What formula did they give you for this?

hoeny123 wrote:4. Calculate the 25th and 75th percentile of the clients’ age.

Start with the cumulative frequencies. :wink:
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