# Statistics

posted by .

Suppose that the weight of male babies less than 2 months old is normally distributed with mean 11.5 pounds and standard deviation 2.7 pounds. A sample of 36 babies is selected. What is the probability that the average weight of the samlpe is less than 11.29 pounds?

• Statistics -

Use z-scores and a z-table for this problem. Because you are given a sample size, you will need to include the sample size in the calculation:

z = (x - mean)/(sd/√n)

z = (11.29 - 11.5)/(2.7/√36)

Finish the calculation. Use the z-table to find the probability (remember that the problem is asking "less than 11.29" when looking at the table).

I hope this will help get you started.

## Similar Questions

1. ### Statisitics:Standard Deviation of Population and o

Standard Deviation of Population and of a Sample The weight of newborn children in the United States vary according to the normal distribution with mean 7.7 pounds and standard deviation 1.68 pounds. The government classifies a newborn …
2. ### Statistics

The Gibbs Baby Food Company wishes to compare the weight gain of infants using their brand versus their competitorâ€™s brand. A sample of 40 babies using the Gibbs products revealed a mean weight gain of 7.6 pounds in the first 3 months …
3. ### statistics

Assuming that the weights of newborn babies are normally distributed with mean 6.5 pounds and standard deviation 1.2 pounds, how many babies in a group of 80 do we expect to weigh more than 8.9 pounds?
4. ### Statistics

Suppose that the birth weight of newborn babies in the U.S is normally distributed with a mean of 7 pounds and a standard deviation of 1.6 pounds. Let the random variable X be the birth weight of a randomly selected record of live …
5. ### Statistics

Suppose that the weight of male babies less than 2 months old is normally distributed with mean 11.5 pounds and standard deviation 2.7 pounds. What proportion of babies weigh less than 11.00 pounds?
6. ### Statistics

The weights of male babies less than 2 months old in the United States is normally distributed with a mean of 11.5 pounds and a standard deviation of 2.7 pounds. Find the 80th percentile score for these weights.
7. ### Math

The weights of male babies less than 2 months old in the United States is normally distributed with a mean of 11.5 pounds and a standard deviation of 2.7 pounds. How do I find the 80th percentile for these weights?
8. ### Statistics

The weights of male babies less than 2 months old in the United States is normally distributed with a mean of 11.5 pounds and a standard deviation of 2.7 pounds. Find the 80th percentile score for these weights. I don't have a table, …
9. ### Statistics

Suppose that the weight of male babies less than 2 months old is normally distributed with mean 11.5 pounds and standard deviation 2.7 pounds. A sample of 36 babies is selected. What is the probability that the average weight of the …
10. ### Statistics

Suppose that the weight of male babies less than 2 months old is normally distributed with mean 11.5 pounds and standard deviation 2.7 pounds. A sample of 36 babies is selected. What is the probability that the average weight of the …

More Similar Questions