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zvonat [6]
4 years ago
13

Evaluate the expression when y=-7. y? +4y-1

Mathematics
1 answer:
Delicious77 [7]4 years ago
5 0

Answer:

20

Step-by-step explanation:

y^2+4y-1=(-7)^2+4(-7)-1=(-7)(-7)-28-1=49-28-1=21-1=20

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Philip Morris wishes to determine if there is a difference between the proportion of women and proportion of men who smoke cigar
uranmaximum [27]

Answer:

Step-by-step explanation:

This is a test of 2 population proportions. Let 1 and 2 be the subscript for the women and men who smoke respectively. The population proportion of women and men who smoke would be p1 and p2 respectively.

p1 - p2 = difference in the proportion of women and men who smoke.

The null hypothesis is

H0 : p1 = p2

p1 - p2 = 0

The alternative hypothesis is

Ha : p1 > p2

p1 - p2 > 0

it is a right tailed test

Sample proportion = x/n

Where

x represents number of success(number of complaints)

n represents number of samples

For women

x1 = 14

n1 = 110

p1 = 14/110 = 0.13

For men,

x2 = 7

n2 = 95

p2 = 7/95 = 0.07

The pooled proportion, pc is

pc = (x1 + x2)/(n1 + n2)

pc = (14 + 7)/(110 + 95) = 0.1

1 - pc = 1 - 0.1 = 0.9

z = (p1 - p2)/√pc(1 - pc)(1/n1 + 1/n2)

z = (0.13 - 0.07)/√(0.1)(0.9)(1/110 + 1/95)

z = 1.47

From the options given, the test statistic is

e. none of these is correct.

Since it is a right tailed test, we will look at the area to the right of z = 1.47. The p value would be

p value = 1 - 0.9292 = 0.078

Since alpha, 0.005 < than the p value, 0.078, then we would fail to reject the null hypothesis. Therefore, the data does not indicate that the proportion of women who smoke cigarettes is higher than the proportion of men who do at α=.005

8 0
3 years ago
The National Aeronautics and Space Administration (NASA) purchased a new solar-powered battery guaranteed to have a failure rate
Reptile [31]

Answer:

The probability that all three batteries would fail is given as:

= 0.000125

Step-by-step explanation:

Given that the probability of the new battery failing = 1/20 or 0.05,

Therefore, the probability that all three batteries would fail is given as:

= Probability of battery A failing * Probability of battery B failing * Probability of battery C failing

= P(A)*P(B)*P(C)

= 0.05 * 0.05 * 0.05

= 0.000125

5 0
3 years ago
A hiker travels at a speed of 3 miles per hour for 3 hours.How far does the hiker travel in that time?
Lady bird [3.3K]
3×3=9 miles. As a result, hiker traveled total 9 miles in that time. Hope it help!
3 0
4 years ago
A certain fraction is greater than 2. The denominator is 8. What must be true about the numerator?
Volgvan

Answer:

The numerator must be greater than 16

Step-by-step explanation:

We are told that a certain fraction is greater than 2. Thus, if the numerator and denominator are x and y respectively, then we have;

x/y > 2

We are further told that the denominator is 8.

Thus;

x/8 > 2

Multiply both sides by 8 to give;

x > 16

Thus,the numerator must be greater than 16.

5 0
3 years ago
3x+9y=75<br>8x+5y=67 <br>what is x and y?
slava [35]

There are many ways to solve simultaneous linear equations. One of my favorite for finding integer solutions is graphing. The attached graph shows the solution to be ...

... (x, y) = (4, 7)

_____

You can also use Cramer's Rule, or the Vedic math variation of it, which tells you the solution to

ax+by=c\\dx+ey=f

is given by

x=\dfrac{bf-ec}{\Delta}\\\\y=\dfrac{cd-fa}{\Delta}\qquad\text{where $\Delta=bd-ea$}

Here, that means

... x = (9·67-5·75)/(9·8-5·3) = 228/57 = 4

... y = (75·8-67·3)/57 = 399/57 = 7

_____

A (graphing) calculator greatly facilitates either of these approaches.

8 0
3 years ago
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