As the average of the sample suggests that the true average penetration of the sample could be greater than the 50 mils established, we formulate our hypothesis as follow

$H_0$ : The true average penetration is 50 mils

$H_a$ : The true average penetration is > 50 mils

Since we are trying to see if the true average is greater than 50, this is a right-tailed test.

If the level of confidence is α = 0.05 then the $z_\alpha$ score against we are comparing with, is 1.64 (this is because the area under the normal curve N(0;1) to the right of 1.64 is 0.05)

The z-score associated with this test is

$z=\frac{\bar x-\mu}{s/\sqrt{n}}$

where

$\bar x$ = mean of the sample

$\mu$ = average established by the specification

s = standard deviation of the sample

n = size of the sample

Computing this value of z we get z = 3.42

Since z > $z_\alpha$ we can conclude that the sample has not met the required specification.

5 0

3 years ago

Please answer this correctly

kiruha [24]

I think they are at 7:10 pm

6 0

3 years ago

Read 2 more answers

Tell whether the triangles are similar or not.

Colt1911 [192]

Answer: Are

Explaning

I think they are similiar because there is parralel lines they are perpendicular and opposite angles are equal making 25 = its oppisite side

4 0

2 years ago

mr. Smith has twice as much money as mr. hairy the average amount of money they have is $489 how much money does mr. Smith have

Darya [45]

Ok, so this one requires you to set up an equation that makes sense....(mr. Smith + mr. Harry)/2= 489...that is the average money from the problem....ok so let’s add some variables now and make it look like math. 2x is mr smith from the first sentence. X is mr. Harry. This yields

(2x+x)/2=489.....use inverse operations to yield
2x+x=978

Combine like terms to get

3x=978

Then divide by 3
To give you x=326

What does x tell you?
X= harry = 326
2x = Smith = 652

To check add them together and divide by 2 to get the average....489

6 0

3 years ago