For a chemistry lab, you used 2 ounces of calcium sulfate, 2.5 pounds of copper, and

You rent a surf board for $12 per hour. Your cost before the tax is added is $96

Rzqust [24]

Answer:8 hours

Step-by-step explanation: divide 96\12 and then that’s how many hours

4 0

4 years ago

Cell phone usage differs by gender. The role of cell phone in modern life was investigated by Pew Internet and American life pro

ahrayia [7]

Answer:

A) Two populations: American men and American women, as it estimated from the broad of the survey.

B) The proportion of men that sometimes do not drive safely while talking or texting on cell phone is 32%, and the proportion of women that sometimes do not drive safely while talking or texting on cell phone is 25%.

C) There is enough evidence to support the claim that the proportion of men and women who used their cell phone in an emergency differ significantly (P-value=0.014).

Step-by-step explanation:

A. We have two populations: American men and American women. This are the populations from which we want to infere the difference of means.

B. The estimation of the proportion is already shown in the question:

The proportion of men that sometimes do not drive safely while talking or texting on cell phone is 32%, and the proportion of women that sometimes do not drive safely while talking or texting on cell phone is 25%.

These are unbiased estimators of the populations proportions.

C. This is a hypothesis test for the difference between proportions.

The claim is that the proportion of men and women who used their cell phone in an emergency differ significantly.

Then, the null and alternative hypothesis are:

$H_0: \pi_1-\pi_2=0\\\\H_a:\pi_1-\pi_2\neq 0$

The significance level is 0.05.

The sample 1 (men), of size n1=643 has a proportion of p1=0.71.

The sample 2 (women), of size n2=643 has a proportion of p2=0.77.

The difference between proportions is (p1-p2)=-0.06.

$p_d=p_1-p_2=0.71-0.77=-0.06$

The pooled proportion, needed to calculate the standard error, is:

$p=\dfrac{X_1+X_2}{n_1+n_2}=\dfrac{457+495.11}{643+643}=\dfrac{952}{1286}=0.7403$

The estimated standard error of the difference between means is computed using the formula:

$s_{p1-p2}=\sqrt{\dfrac{p(1-p)}{n_1}+\dfrac{p(1-p)}{n_2}}=\sqrt{\dfrac{0.7403*0.2597}{643}+\dfrac{0.7403*0.2597}{643}}\\\\\\s_{p1-p2}=\sqrt{0.0003+0.0003}=\sqrt{0.0006}=0.0245$

Then, we can calculate the z-statistic as:

$z=\dfrac{p_d-(\pi_1-\pi_2)}{s_{p1-p2}}=\dfrac{-0.06-0}{0.0245}=\dfrac{-0.06}{0.0245}=-2.45$

This test is a two-tailed test, so the P-value for this test is calculated as (using a z-table):

$P-value=2\cdot P(z$

As the P-value (0.014) is smaller than the significance level (0.05), the effect is significant.

The null hypothesis is rejected.

There is enough evidence to support the claim that the proportion of men and women who used their cell phone in an emergency differ significantly.

3 0

4 years ago

The following statements are made about some number: a) It is prime b) It is odd number and less than 5 c) It is an even number

rusak2 [61]

a) It is prime - 2, 3
b) It is odd number and less than 5 - 1, 3,
c) It is an even number - 2,4
d) It is 3

If a) and c) is true, then Number is 2. 2 is prime and 2 is even.
b) and c) is false.

3 0

3 years ago

Read 2 more answers

Andrew bought 3 pairs of shoe shoes for 165 dollars and what if he bought 11 shoes how much money

LuckyWell [14K]

3 pairs cost $165
165/3 = 55
1 pair cost $55
Eleven pairs would cost 11(55) = $605

4 0

3 years ago

Estimate the circumference. Use 3.14 or 22/7 to approximate π.

Anon25 [30]

You have to plug in all the numbers to the circumference formula and solve!
circumference formula: $\pi d$ or $2 \pi r$

3.14(12.5) = ?
39.25

The answer is d. 39.25

3 0

3 years ago