The mean temperature for the first 4 days in January was 1°C.

The mean gross annual incomes of certified welders are normally distributed with the mean of $20,000 and a standard deviation of

grandymaker [24]

Answer:

At the 0.10 level of significance the z table gives critical values of -1.645 and 1.645 for two-tailed test.

Step-by-step explanation:

We are given that the mean gross annual incomes of certified welders are normally distributed with the mean of $20,000 and a standard deviation of $2,000.

The ship building association wishes to find out whether their welders earn more or less than $20,000 annually.

Let $\mu$ = mean gross annual incomes of certified welders

So, Null Hypothesis, $H_0$ : $\mu$ = $20,000

Alternate hypothesis, $H_A$ : $\mu \neq$ $20,000

Here, null hypothesis states that the mean income of welders is equal to $20,000.

On the other hand, alternate hypothesis states that the mean income of welders is not $20,000.

Also, the test statistics that would be used here is One-sample z test statistics as we know about the population standard deviation;

T.S. = $\frac{\bar X-\mu}{\frac{\sigma}{\sqrt{n} } }$ ~ N(0,1)

where, $\bar X$ = sample mean income

$\sigma$ = population standard deviation = $2,000

n = sample size

Now, at the 0.10 level of significance the z table gives critical values of -1.645 and 1.645 for two-tailed test.

3 0

2 years ago

Mr. Schwartz builds toy cars. He begins the week with a supply of 85 wheels, and uses 4 wheels for each car he builds. Mr. Schwa

Reptile [31]

When will he have less than 40 wheels left? Well you can make the equation...

85-4x=40

And then solve for x.

85-4x=40

-4x=-45

x=11 1/4 rounded up to 12

answer: He will have less than 40 wheels left after he has built 12 cars.

5 0

2 years ago

5. You deposit $300 in an account Urat pays 1.48% annual interest. What is the balance after 1 year if the

kirill [66]

Answer:

The correct option is (A) $304.47.

Step-by-step explanation:

The formula to compute the future value (FV) of an amount (A), compounded daily at an interest rate of r%, for a period of n years is:

$FV=A\times [1+\frac{r\%}{365}]^{n\times 365}$

The information provided is:

A = $300

r% = 1.48%

n = 1 year

Compute the future value as follows:

$FV=A\times [1+\frac{r\%}{365}]^{n\times 365}$

$=300\times [1+\frac{0.0148}{365}]^{365}\\\\=300\times (1.00004055)^{365}\\\\=300\times 1.014911\\\\=304.4733\\\\\approx \$304.47$

Thus, the balance after 1 year is $304.47.

The correct option is (A).

8 0

1 year ago

Josephine bought 8 packets of biscuits. Each packet had a mass of 500 g

Nataly_w [17]

Answer: 985 g

Step-by-step explanation:

Total mass = 8 × 500g = 4000g

Let the three new packs be X, Y, and Z, for first, second, and third pack respectively.

4000g = X + Y + Z

let's put X and Z in terms of Y, since we're trying to solve for the second pack.

X = 2Y, and Z = Y + 60

Therefore,

4000 = X + Y + Z

4000 = 2Y + Y +Y + 60

4000 = 4Y +60

4000 - 60 = 4Y

3940 = 4Y

3940 ÷ 4 = Y

985g = Y = mass of the second pack

7 0

2 years ago

A ball is thrown upward and outward from a height of 77 feet. the height of the ball, f(x), in feet, can be modeled by f left

Oksi-84 [34.3K]

From the given function modeling the height of the ball:
f(x)=-0.2x^2+1.4x+7
A] The maximum height of the ball will be given by:
At max height f'(x)=0
from f(x),
f'(x)=-0.4x+1.4
solving for x we get:
-0.4x=-1.4
x=3.5ft
thus the maximum height would be:
f(3.5)=-0.2(3.5)^2+1.4(3.5)+7
f(3.5)=9.45 ft

b]
How far from where the ball was thrown did this occur:
from (a), we see that at maximum height f'(x)=0
f'(x)=-0.4x+1.4
solving for x we get:
-0.4x=-1.4
x=3.5ft
This implies that it occurred 3.5 ft from where the ball was thrown.

c] How far does the ball travel horizontally?
f(x)=-0.2x^2+1.4x+7
evaluationg the expression when f(x)=0 we get:
0=-0.2x^2+1.4x+7
Using quadratic equation formula:
x=-3.37386 or x=10.3739
We leave out the negative and take the positive answer. Hence the answer 10.3739 ft horizontally.

6 0

2 years ago