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Studentka2010 [4]
3 years ago
11

A random sample of 36 students at a community college showed an average age of 25 years. Assume the ages of all students at the

college are normally distributed with a standard deviation of 1.8 years. The 98% confidence interval for the average age of all students at this college is _____.
Mathematics
1 answer:
Pavel [41]3 years ago
8 0

Answer:

98% confidence interval for the average age of all students is [24.302 , 25.698]

Step-by-step explanation:

We are given that a random sample of 36 students at a community college showed an average age of 25 years.

Also, assuming that the ages of all students at the college are normally distributed with a standard deviation of 1.8 years.

So, the pivotal quantity for 98% confidence interval for the average age is given by;

             P.Q. = \frac{\bar X - \mu}{\frac{\sigma}{\sqrt{n} } } ~ N(0,1)

where, \bar X = sample average age = 25 years

            \sigma = population standard deviation = 1.8 years

            n = sample of students = 36

            \mu = population average age

So, 98% confidence interval for the average age, \mu is ;

P(-2.3263 < N(0,1) < 2.3263) = 0.98

P(-2.3263 < \frac{\bar X - \mu}{\frac{\sigma}{\sqrt{n} } } < 2.3263) = 0.98

P( -2.3263 \times {\frac{\sigma}{\sqrt{n} } < {\bar X - \mu} < 2.3263 \times {\frac{\sigma}{\sqrt{n} } ) = 0.98

P( \bar X - 2.3263 \times {\frac{\sigma}{\sqrt{n} } < \mu < \bar X +2.3263 \times {\frac{\sigma}{\sqrt{n} } ) = 0.98

98% confidence interval for \mu = [ \bar X - 2.3263 \times {\frac{\sigma}{\sqrt{n} } , \bar X +2.3263 \times {\frac{\sigma}{\sqrt{n} } ]

                                                  = [ 25 - 2.3263 \times {\frac{1.8}{\sqrt{36} } , 25 + 2.3263 \times {\frac{1.8}{\sqrt{36} } ]

                                                  = [24.302 , 25.698]

Therefore, 98% confidence interval for the average age of all students at this college is [24.302 , 25.698].

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Natali [406]

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-49, -43, -39, -18, -14, -12, -9

Mean is adding all the numbers together and dividing the sum by how many numbers there are in the data set

-49 + (-43) + (-39) + (-18) + (-14) + (-12) + (-9) = -184

There are seven numbers so divide -184 by 7:

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Median is the number in the middle. Take away the smallest number and the biggest number on each layer until you get to the middle

-49, -43, -39, -18, -14, -12, -9

       -43, -39, -18, -14, -12

              -39, -18, -14

                      -18 <-------------------Median

Mode is whatever number appears the most often in the data. In this case all the numbers appear only once so there is no mode

Range is subtracting the largest number by the smallest number

-9 - (-49) = 40

2. Data in order

13, 13, 13, 15, 21, 23, 25, 37

Outlier is the number that is a number that is rather far from the other number in the data

a. In this case the outlier is 37

b. 13 + 13 + 13 + 15 + 21 + 23 + 25 + 37 = 160

160 ÷ 8 = 20

c. 13 + 13 + 13 + 15 + 21 + 23 + 25  = 123

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alexdok [17]

Answer:

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Step-by-step explanation:

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Step-by-step explanation:

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In this question, the vertex is (6,\, 5), such that h = 6 and k = 5. There would exist a constant a such that the equation of this parabola would be:

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