A wheel has a radius of 15 cm . approximately how far does it travel in 4 revolutions?

A college student is interested in investigating the TV-watching habits of her classmates and surveys 20 people on the number of

Alla [95]

Answer:

80% confidence interval of the true average number of hours of TV watched per week is [8.28 hours, 11.02 hours].

Step-by-step explanation:

We are given that a college student is interested in investigating the TV-watching habits of her classmates and surveys 20 people on the number of hours they watch per week. The results are provided below;

Hours of TV per week (X): 6, 14, 13, 6, 16, 10, 19, 4, 5, 5, 18, 8, 7, 14, 8, 8, 9, 12, 6, 5.

Firstly, the Pivotal quantity for 80% confidence interval for the true average is given by;

P.Q. = $\frac{\bar X-\mu}{\frac{s}{\sqrt{n} } }$ ~ $t_n_-_1$

where, $\bar X$ = sample mean number of hours of TV watched per week = $\frac{\sum X}{n}$ = 9.65

s = sample standard deviation = $\sqrt{\frac{\sum (X -\bar X)^{2} }{n-1} }$ = 4.61

n = sample of people = 20

$\mu$ = true average number of hours of TV watched per week

Here for constructing 80% confidence interval we have used One-sample t-test statistics as we don't know about population standard deviation.

So, 80% confidence interval for the true average, $\mu$ is ;

P(-1.33 < $t_1_9$ < 1.33) = 0.80 {As the critical value of t at 19 degrees of

freedom are -1.33 & 1.33 with P = 10%}

P(-1.33 < $\frac{\bar X-\mu}{\frac{s}{\sqrt{n} } }$ < 1.33) = 0.80

P( $-1.33 \times {\frac{s}{\sqrt{n} } }$ < ${\bar X-\mu}$ < $1.33 \times {\frac{s}{\sqrt{n} } }$ ) = 0.80

P( $\bar X-1.33 \times {\frac{s}{\sqrt{n} } }$ < $\mu$ < $\bar X+1.33 \times {\frac{s}{\sqrt{n} } }$ ) = 0.80

80% confidence interval for $\mu$ = [ $\bar X-1.33 \times {\frac{s}{\sqrt{n} } }$ , $\bar X+1.33 \times {\frac{s}{\sqrt{n} } }$ ]

= [ $9.65-1.33 \times {\frac{4.61}{\sqrt{20} } }$ , $9.65+1.33 \times {\frac{4.61}{\sqrt{20} } }$ ]

= [8.28 hours, 11.02 hours]

Therefore, 80% confidence interval of the true average number of hours of TV watched per week is [8.28 hours, 11.02 hours].

7 0

3 years ago

Macy walked and jogged a total of 4 1/9 miles in Central Park today. If she jogged a distance of 2 2/3 miles, how many miles did

lianna [129]

6 7/9 of a mile is what she walked

7 0

3 years ago

I need help ASAP please and thank u!!!!

disa [49]

Answer:what do you need help with?

Step-by-step explanation:

7 0

3 years ago

Find the measure of each exterior angle of a regular pentagon

lyudmila [28]

Answer:

360

Step-by-step explanation:

The sum of the exterior angles of a regular polygon, irrespective of the number of sides is 360 degrees. If N is the number of sides, each exterior angle will be 360/N degrees. In the present case there 5 sides in a regular pentagon, hence each exterior = 360/5 or 72 degrees.

6 0

4 years ago

8a to the power of 6 times a to the power of 4 over 4a to the power of -3

svetlana [45]

Answer:

(8a)⁻¹⁸

1 / (8a)¹⁸

Step-by-step explanation:

(((8a)^6a)^4/4a))^-3

((8a)^6a*4/4a)^-3

((8a)^6)^-3

(8a)^6*(-3)

(8a)⁻¹⁸

1 / (8a)¹⁸

4 0

3 years ago