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raketka [301]
3 years ago
5

A nurse at a local hospital is interested in estimating the birth weight of infants. how large a sample must she select if she d

esires to be 98% confident that the tue mean is within 3 ounces of sample mean. the standard deviation of birth weights is known to be 6 ounces
Mathematics
1 answer:
enyata [817]3 years ago
7 0
For large sample confidence intervals about the mean you have: 

xBar ± z * sx / sqrt(n) 

where xBar is the sample mean z is the zscore for having α% of the data in the tails, i.e., P( |Z| > z) = α sx is the sample standard deviation n is the sample size
 
We need only to concern ourselves with the error term of the CI, In order to find the sample size needed for a confidence interval of a given size.

z * sx / sqrt(n) = width. 

so the z-score for the confidence interval of .98 is the value of z such that 0.01 is in each tail of the distribution. z = 2.326348 

The equation we need to solve is:
z * sx / sqrt(n) = width 
n = (z * sx / width) ^ 2. 
n = ( 2.326348 * 6 / 3 ) ^ 2 
n = 21.64758 

Since n must be integer valued we need to take the ceiling of this solution.
n = 22 
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Step-by-step explanation:

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mestny [16]

Answer:

x = 9

Step-by-step explanation:

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8 0
2 years ago
What is the answer someone help please
Maru [420]
166.25 thats the answer
4 0
3 years ago
Part A: Find a rational number that is between 5.2 and 5.5. Explain why it is rational. (2 points) Part B: Find an irrational nu
max2010maxim [7]
A rational number can always be represented as a fraction.
5.2 = 52/10 
5.5 = 55/10

A number between them would be 54/10 since 54 is between 52 and 55.

An irrational number cannot be represented as a fraction. A good example of an irrational number is the square root of a number.
sqrt(5.2^2) = 5.2  ----> 5.2^2 = 27.04
sqrt(5.5^2) = 5.5  ----> 5.5^2 = 30.25

The square root of a number between 27.04 and 30.25 will be an irrational number between 5.2 and 5.5
sqrt(28) = 5.2915...
3 0
3 years ago
Help me on 1,2,3,5,and 6 please
arlik [135]
Since most of these are mixed number you have to convert them into improper fractions.
For an example 2 3/4 x 1/2
First you would have the convert 2 3/4
You would add 2 to 3 then multiply 2 to 4
So it would be (2x4) + 3
You keep the denominator of the originally fraction so it would be 11/4
Then to finish you would multiply straight across so
11x1= 11
4x2=8
11/8
1 3/8
Hope this helps!!
8 0
3 years ago
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