mary and cindy can do a typing test in 2 hours. mary can do it in 3 hours less than cindy. how many hours can cindy do it in?

Consider the following hypothesis test: H0: LaTeX: \mu_1-\mu_2=0μ 1 − μ 2 = 0 Ha: LaTeX: \mu_1-\mu_2\ne0μ 1 − μ 2 ≠ 0 The follow

Pavel [41]

Answer:

$z=\frac{104-\bar 106}{\sqrt{\frac{8.4^2}{80}+\frac{7.6^2}{70}}}}=-1.53$

Step-by-step explanation:

Data given and notation

$\bar X_{1}=104$ represent the mean for the sample 1

$\bar X_{2}=106$ represent the mean for the sample 2

$\sigma_{1} =8.4$ represent the population standard deviation for the sample 1

$\sigma_{2}=7.6$ represent the population standard deviation for the sample 2

$n_{1}=80$ sample size for the group 1

$n_{2}=70$ sample size for the group 2

z would represent the statistic (variable of interest)

Concepts and formulas to use

We need to conduct a hypothesis in order to check if the means for the two groups are the same, the system of hypothesis would be:

H0: $\mu_{1}-\mu_{2} =0$

H1: $\mu_{1} -\mu_{2} \neq 0$

If we analyze the size for the samples both are greater than 30 and we know the population deviations so for this case is better apply a z test to compare means, and the statistic is given by:

$z=\frac{\bar X_{1}-\bar X_{2}}{\sqrt{\frac{\sigma^2_{1}}{n_{1}}+\frac{\sigma^2_{2}}{n_{2}}}}$ (1)

z-test: Is used to compare group means. Is one of the most common tests and is used to determine whether the means of two groups are equal to each other.

Calculate the statistic

First we need to calculate the mean and deviation for each sample, after apply the formulas (2) and (3) we got the following results:

And with this we can replace in formula (1) like this:

$z=\frac{104-\bar 106}{\sqrt{\frac{8.4^2}{80}+\frac{7.6^2}{70}}}}=-1.53$

7 0

3 years ago

Marisol wants to determine how many students plan to attend the girls varsity basketball game . Find her mistake and correct it

Contact [7]

Boys bvarsity is wrong and so is Bastet

7 0

3 years ago

In a chemistry lab, you have 2 vinegars. One is 5% acetic acid, and one is 6.5% acetic acid. You want to make 200 ml of a vinega

Iteru [2.4K]

We have 5% and 6.5% acetic acid solutions and we need 200 ml of 6% acetic acid.
Set up two equations:
f means 5% and s means 6.5%
A) f + s = 200
B) .05f + .065s = (.06 * 200)
Multiplying equation A by -.05
A) -.05f -.05s = -10
B) .05f + .065s = 12 then adding both equations:
.015s = 2
 we need 133.33 ml of 6.5% acetic acid and
66.67 ml of 5% acetic acid solution.
 
Source:
http://www.1728.org/mixture.htm

8 0

3 years ago

If tan (theta) =5/4 and cos (theta) < 0 . Find the other trig. functions.

andrew-mc [135]

Tan(theta) = 5/4
sin(theta)/cos (theta)=5/4
cos(theta)=4sin(theta)/5
sin²(theta)+cos²(theta)=1
sin²(theta)+16sin²(iheta)/25=1 /*25
25 sin²(theta)+16 sin²(theta)=25
sin²(theta)=25/41 /√
sin(theta)= $\frac{-5 \sqrt{41} }{41}$
cos(theta)= $\frac{-4 \sqrt{41} }{41}$
cot(theta)= $\frac{4}{5}$
csc(theta)=1/sin(theta)= $\frac{- \sqrt{41} }{5}$
sec(theta)=1/cos(theta)= $\frac{- \sqrt{41} }{4}$

5 0

2 years ago

Help ASAP PLEASE! Right answer only

astra-53 [7]

Answer:

2x-5

Step-by-step explanation:

f(g(x) means stick g(x) into f(x) in place of x

f(x) = 2x+1

f(g(x) ) = 2(g(x)) +1

and we know that g(x) = x-3

so replace g(x) with x-3

f(g(x) ) = 2(x-3) +1

Distribute

f(g(x)) = 2x-6+1

= 2x-5

4 0

3 years ago

mary and cindy can do a typing test in 2 hours. mary can do it in 3 hours less than cindy. how many hours can cindy do it in?​

mary and cindy can do a typing test in 2 hours. mary can do it in 3 hours less than cindy. how many hours can cindy do it in?