Find the value of given shape .

A quality analyst of a tennis racquet manufacturing plant investigates if the length of a junior's tennis racquet conforms to th

Burka [1]

Answer:

Confidence interval : $21.506$ to $24.493$

Step-by-step explanation:

A quality analyst selects twenty racquets and obtains the following lengths:

21, 25, 23, 22, 24, 21, 25, 21, 23, 26, 21, 24, 22, 24, 23, 21, 21, 26, 23, 24

So, sample size = n =20

Now we are supposed to find Construct a 99.9% confidence interval for the mean length of all the junior's tennis racquets manufactured at this plant.

Since n < 30

So we will use t-distribution

Confidence level = 99.9%

Significance level = α = 0.001

Now calculate the sample mean

X=21, 25, 23, 22, 24, 21, 25, 21, 23, 26, 21, 24, 22, 24, 23, 21, 21, 26, 23, 24

Sample mean = $\bar{x}=\frac{\sum x}{n}$

Sample mean = $\bar{x}=\frac{21+25+23+22+24+21+25+21+23+ 26+ 21+24+22+ 24+23+21+ 21+ 26+23+ 24}{20}$

Sample mean = $\bar{x}=23$

Sample standard deviation = $\sqrt{\frac{\sum(x-\bar{x})^2}{n-1}}$

Sample standard deviation = $\sqrt{\frac{(21-23)^2+(25-23)^2+(23-23)^2+(22-23)^2+(24-23)^2+(21-23)^2+(25-23)^2+(21-23)^2+(23-23)^2+(26-23)^2+(21-23)^2+(24-23)^2+(22-23)^2+(24-23)^2+(23-23)^2+(21-23)^2+(21-23)^2+(26-23)^2+(23-23)^2+(24-23)^2}{20-1}}$

Sample standard deviation= s = $1.72$

Degree of freedom = n-1 = 20-1 -19

Critical value of t using the t-distribution table $t_{\frac{\alpha}{2}$ = 3.883

Formula of confidence interval : $\bar{x} \pm t_{\frac{\alpha}{2}} \times \frac{s}{\sqrt{n}}$

Substitute the values in the formula

Confidence interval : $23 \pm 1.73 \times \frac{1.72}{\sqrt{20}}$

Confidence interval : $23 -3.883 \times \frac{1.72}{\sqrt{20}}$ to $23 + 3.883 \times \frac{1.72}{\sqrt{20}}$

Confidence interval : $21.506$ to $24.493$

Hence Confidence interval : $21.506$ to $24.493$

3 0

3 years ago

Read 2 more answers

Evaluate the expression if a = 9 and b = 2. 5(a 3b) 20 51 70 75

devlian [24]

5(a + 3b) = 5(9 + 3(2)) = 5(9 + 6) = 5(15) = 75

5 0

3 years ago

The slope of a line is -1/3, and the y-intercept is 10/3. What is the equation of the line written in general form?

Y_Kistochka [10]

The answer is: [B]: " x + 3y + 10 = 0 " .
______________________________________________________
Explanation:
______________________________________________________
Note the equation for a line; in 'slope-intercept form': "y = mx + b" ;

in which "y" is isolated alone, as a single variable, on the left-hand side of the equation;
"m" = the slope of the line; and is the co-efficient of "x" ;
b = the "y-intercept"; (or the "y-coordinate of the point of the "y-intercept").
______________________________________________________
So, given the information in this very question/problem:
______________________________________________________
slope = m = (-1/3) ;
b = y-intercept = (10/3) ;
______________________________________________________
And we can write the equation of the line; in "slope-intercept form"; that is:
______________________________________________________
" y = mx + b " ; as:
______________________________________________________

" y = (-1/3)x + (10/3) " ;
______________________________________________________
Now, the problem asks for the equation of this line; in "general form"; or "standard format"; which is:
________________________________________
"Ax + By + C = 0 " ;
________________________________________
So; given:
____________________________________
" y = (-1/3)x + (10/3) " ;
____________________________________
We can multiply the ENTIRE EQUATION (both sides) by "3" ; to get rid of the "fractions" ;

→ 3* { y = (-1/3)x + (10/3) } ;

→ 3y = -1x + 10 ;

↔ -1x + 10 = 3y ;

Subtract "(3y)" from each side of the equation:
____________________________________
-1x + 10 − 3y = 3y − 3y ;

to get:

-1x + 10 − 3y = 0 ;

↔ -1x − 3y − 10 = 0 ;

→ This is not one of the "3 (THREE) answer choices given" ;

→ So, multiply the ENTIRE EQUATION (both sides); by "-1" ; as follows:

-1 * {-1x − 3y − 10 = 0} ;

to get:
______________________________________________________
→ " x + 3y + 10 = 0 " ; which is: "Answer choice: [B] ."
______________________________________________________
Note that is equation is in the "standard format" ;
→ " Ax + By + C = 0 " .
______________________________________________________

6 0

3 years ago

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A closet contains 5 short-sleeve shirts and 3 long-sleeve shirts. Two shirts are chosen from the closet without looking. What is

Gennadij [26K]

D. There is a 5/8 chance each time. You would multiply that together to get the answer seen in D.

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3 years ago

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Please answer the question above and pick an answer choice from the ones provided

Ira Lisetskai [31]

Answer: