A car rental service charges $50 plus a fee of $25 for each day. If a rental costs $175, how many days was the car rented?

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

Pavel [41]

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].

8 0

3 years ago

FASTTT HURRYYYY PLEASEEEEEE<br> The pair of figures is similar. Find the missing side.

Vladimir [108]

The answer is x=12 :)

6 0

3 years ago

Write this expression so that its denominator, if any, is a positive integer.<br> 2/(3+sqrt(7))

Tanzania [10]

Answer:

The Answer is 3 - sqrt7

Step-by-step explanation:

2/3 + sqrt7 the starting equation

You multiply it by the conjugate which is 3 - sqrt7

= 2(3 - sqrt7) / (3 + sqrt7) (3 - sqrt7) the equation after you multiply by 3 - sqrt7

(3 + sqrt7) (3 - sqrt7) = 2

= 2(3 - sqrt7) / 2 the equation after you simplify (3 + sqrt7) (3 - sqrt7)

Divide out the 2's

= 3 - sqrt7/1 the equation after you divide out the 2's

= 3 - sqrt7 is THE ANSWER

7 0

2 years ago

Point O is between points Mand N on line segment MN. O is the midpoint of line segment MN if

s2008m [1.1K]

Diagram:
M------------O-------------N
................. ^ midpoint
Obviously if O is the *mid*point, then it is exactly halfway between M and N. That also means it has bisected the segment into two equal parts.
On one side you have MO (or OM, if you like)
On the other side you have ON.
In order for O to be the midpoint:
ON = OM

8 0

3 years ago

X^2 -18x +81=0 factor it

nasty-shy [4]

Answer:

x=9

Step-by-step explanation:

81 is the product of -9 & -9. -9-9=-18. Therefore, (x-9)^2=0, and you get that x=9.

6 0

3 years ago