The ratio of a right angle to the total degrees in a circle is

A random sample of 9 wheels of cheese yielded the following weights in pounds has a sample mean of 20.90 and a sample variance o

Ronch [10]

Answer:

$2.002 \leq \sigma^2 \leq 11.365$

Step-by-step explanation:

1) Data given and notation

s represent the sample standard deviation

$s^2$ represent the sample variance

n=9 the sample size

Confidence=90% or 0.90

A confidence interval is "a range of values that’s likely to include a population value with a certain degree of confidence. It is often expressed a % whereby a population mean or variance lies between an upper and lower interval".

The margin of error is the range of values below and above the sample statistic in a confidence interval.

The Chi Square distribution is the distribution of the sum of squared standard normal deviates .

2) Calculating the confidence interval

The confidence interval for the population variance is given by the following formula:

$\frac{(n-1)s^2}{\chi^2_{\alpha/2}} \leq \sigma \frac{(n-1)s^2}{\chi^2_{1-\alpha/2}}$

On this case we need to find the sample standard deviation with the following formula:

$s=sqrt{\frac{\sum_{i=1}^9 (x_i -\bar x)^2}{n-1}}
The sample variance given was [tex]s^2=3.45$

The next step would be calculate the critical values. First we need to calculate the degrees of freedom given by:

$df=n-1=9-1=8$

Since the Confidence is 0.90 or 90%, the value of $\alpha=0.1$ and $\alpha/2 =0.05$ , and we can use excel, a calculator or a table to find the critical values.

The excel commands would be: "=CHISQ.INV(0.05,8)" "=CHISQ.INV(0.95,8)". so for this case the critical values are:

$\chi^2_{\alpha/2}=15.507$

$\chi^2_{1- \alpha/2}=2.732$

And replacing into the formula for the interval we got:

$\frac{(9)(3.45)}{15.507} \leq \sigma \frac{(9)(3.45)}{2.732}$

$2.002 \leq \sigma^2 \leq 11.365$

7 0

3 years ago

while teresa listened to the radio, there were 9minutes of commercials, 12 minutes of talk, and 29minutes of music what percent

ahrayia [7]

To find this, you'll want to divide the amount of music by the total amount of time. 29/(9+12+29) = 29/50 = 58/100 = 58%

4 0

3 years ago

Which shows the graph of the solution set of 3y – 2x > –18?

nikdorinn [45]

Answer:

Graph of the inequality 3y-2x>-18 is given below.

Step-by-step explanation:

We are given the inequality, 3y-2x>-18

Now, using the 'Zero Test', which states that,

After substituting the point (0,0) in the inequality, if the result is true, then the solution region is towards the origin. If the result is false, then the solution region is away from the origin'.

So, after substituting (0,0) in 3y-2x>-18, we get,

3\times 0-2\times 0>-18

i.e. 0 > -18, which is true.

Thus, the solution region is towards the origin.

Hence, the graph of the inequality 3y-2x>-18 is given below.

8 0

3 years ago

M–[(m–n)÷(−2)](−5), if m=−4, n=−6

Marrrta [24]

$- 4 - (( - 4 + 6) \div ( - 2))( - 5) = \\ = - 4 - (2 \div ( - 2))( - 5) = \\ = - 4 - ( - 1)( - 5) = - 4 - 5 = \\ = - 9$

5 0

2 years ago

Read 2 more answers

The volume of a cube is 512 cm3 . What is the area, in square centimetres, of each side of the cube?

lesantik [10]

Answer:

Step-by-step explanation:

V of a cube is s^3

V = 512

s = cube root of (V)

s = cube root of 512 cm^3

s = 8

The area of one face of the cube is s^2

s = 8

Area 1 face = 8^2

Area of 1 face = 64 cm^2

4 0

2 years ago