statistics

posted by .

The average age for licensed drivers in the county
is μ  40.3 years with a standard deviation of  
13.2 years.
a. A researcher obtained a random sample of n  16
parking tickets and computed an average age of
M  38.9 years for the drivers. Compute the z-score
for the sample mean and find the probability of
obtaining an average age this young or younger
for a random sample of licensed drivers. Is it
reasonable to conclude that this set of n  16
people is a representative sample of licensed
drivers?
b. The same researcher obtained a random sample of
n  36 speeding tickets and computed an average
age of M  36.2 years for the drivers. Compute the
z-score for the sample mean and find the probability
of obtaining an average age this young or
younger for a random sample of licensed drivers.
Is it reasonable to conclude that this set of n  36
people is a representative sample of licensed
drivers?

  • statistics -

    Z = (mean1 - mean2)/standard error (SE) of difference between means

    SEdiff = √(SEmean1^2 + SEmean2^2)

    SEm = SD/√n

    If only one SD is provided, you can use just that to determine SEdiff.

    Find table in the back of your statistics text labeled something like "areas under normal distribution" to find the proportion/probability of the Z scores.

Respond to this Question

First Name
School Subject
Your Answer

Similar Questions

  1. probability and statistics

    the average age for licensed drivers in the country is u=40.3 years with a standard deviation of o= 13.2 years. a. a researcher obtained a random sample of n=16 parking tickets and computed an average age of m=38.9 years for the drivers. …
  2. statistics

    An April 15, 2002 report in Time Magazine stated that the average age for women to marry in the United States is now 24.9 years of age. If the standard deviation is assumed to be 4.9 years, find the probability that a random sample …
  3. statistics

    An April 15, 2002 report in Time Magazine stated that the average age for women to marry in the United States is now 24.9 years of age. If the standard deviation is assumed to be 4.9 years, find the probability that a random sample …
  4. STATISTICS

    An April 15, 2002 report in Time Magazine stated that the average age for women to marry in the United States is now 24.9 years of age. If the standard deviation is assumed to be 4.9 years, find the probability that a random sample …
  5. statistics

    An April 15, 2002 report in Time Magazine stated that the average age for women to marry in the United States is now 25.1 years of age. If the standard deviation is assumed to be 4.6 years, find the probability that a random sample …
  6. Statistics

    An April 15, 2002 report in Time Magazine stated that the average age for women to marry in the United States is now 24.5 years of age. If the standard deviation is assumed to be 4.1 years, find the probability that a random sample …
  7. statistics

    An April 15, 2002 report in Time Magazine stated that the average age for women to marry in the United States is now 25.6 years of age. If the standard deviation is assumed to be 4.1 years, find the probability that a random sample …
  8. Statistics

    An April 15, 2002 report in Time Magazine stated that the average age for women to marry in the United States is now 25.9 years of age. If the standard deviation is assumed to be 4.3 years, find the probability that a random sample …
  9. statistics

    The average age for licensed drivers in a county is ยต= 42.6, σ= 12 and the distribution is approximately normal. A county police officer was interested in whether the average age of those receiving parking tickets in the county …
  10. social statistics

    a smoking researcher is interested in estimating the average age when cigarette smokers first began to smoke. Taking a random sample of 25, she determines a sample mean of 16.8 years and a sample deviation of 1.5 years. Construct a …

More Similar Questions