I need help, please. I will try to give brainliest!!!

HELP HELP!!!! YOU WILL GET BRAINLIEST!! PLEASE!!!

LiRa [457]

Um idk sorry lol that’s way to hard for me

5 0

3 years ago

5) In a certain supermarket, a sample of 60 customers who used a self-service checkout lane averaged 5.2 minutes of checkout tim

Ne4ueva [31]

Answer:

$\S^2_p =\frac{(60-1)(3.1)^2 +(72 -1)(2.8)^2}{60 +72 -2}=8.643$

$S_p=2.940$

$t=\frac{(5.2 -6.1)-(0)}{2.940\sqrt{\frac{1}{60}+\frac{1}{72}}}=-1.751$

$df=60+72-2=130$

$p_v =P(t_{130}$

Assuming a significance level of $\alpha=0.05$ we have that the p value is lower than this significance level so then we can conclude that the mean for checkout time is significantly less for people who use the self-service lane

Step-by-step explanation:

Data given

Our notation on this case :

$n_1 =60$ represent the sample size for people who used a self service

$n_2 =72$ represent the sample size for people who used a cashier

$\bar X_1 =5.2$ represent the sample mean for people who used a self service

$\bar X_2 =6.1$ represent the sample mean people who used a cashier

$s_1=3.1$ represent the sample standard deviation for people who used a self service

$s_2=2.8$ represent the sample standard deviation for people who used a cashier

Assumptions

When we have two independent samples from two normal distributions with equal variances we are assuming that

$\sigma^2_1 =\sigma^2_2 =\sigma^2$

The statistic is given by:

$t=\frac{(\bar X_1 -\bar X_2)-(\mu_{1}-\mu_2)}{S_p\sqrt{\frac{1}{n_1}+\frac{1}{n_2}}}$

And t follows a t distribution with $n_1+n_2 -2$ degrees of freedom and the pooled variance $S^2_p$ is given by this formula:

$\S^2_p =\frac{(n_1-1)S^2_1 +(n_2 -1)S^2_2}{n_1 +n_2 -2}$

System of hypothesis

Null hypothesis: $\mu_1 \geq \mu_2$

Alternative hypothesis: $\mu_1 < \mu_2$

This system is equivalent to:

Null hypothesis: $\mu_1 - \mu_2 \geq 0$

Alternative hypothesis: $\mu_1 -\mu_2 < 0$

We can find the pooled variance:

$\S^2_p =\frac{(60-1)(3.1)^2 +(72 -1)(2.8)^2}{60 +72 -2}=8.643$

And the deviation would be just the square root of the variance:

$S_p=2.940$

The statistic is given by:

$t=\frac{(5.2 -6.1)-(0)}{2.940\sqrt{\frac{1}{60}+\frac{1}{72}}}=-1.751$

The degrees of freedom are given by:

$df=60+72-2=130$

And now we can calculate the p value with:

$p_v =P(t_{130}$

Assuming a significance level of $\alpha=0.05$ we have that the p value is lower than this significance level so then we can conclude that the mean for checkout time is significantly less for people who use the self-service lane

5 0

3 years ago

Write an equation of the line that passes through (2001, 35) and (2004.5, 16.1 ) points

Allisa [31]

Answer: If you are looking for Slope-Intercept form (y=mx+b), It would be...

y=-5.4x+10840.4.

If you are looking for Point-Slope form, it would be...

y=-5.4x+10840.4.

Step-by-step explanation: Write in Slope-Intercept from, y=mx+b.

Point-Slope form : Use the Point-Slope formula, y-y1=m(x-x1) to find the equation of the line.

I hope this helps you out! ☺

7 0

3 years ago

Y/−7 = 1 /4 what does y =

Studentka2010 [4]

Answer:

y = - $\frac{7}{4}$

Step-by-step explanation:

$\frac{y}{-7}$ = $\frac{1}{4}$ ( cross- multiply )

4y = - 7 ( divide both sides by 4 )

y = - $\frac{7}{4}$

4 0

3 years ago

Read 2 more answers

How do I solve this equation to get the solution?<br><br> y= -2x - 1<br><br> -3x + 6y = 24

swat32

There are a few ways to solve this. The method I will use is the substitution method. Since they give us a "y = " statement, we can replace the y in the second equation with what it gives us to the right of the equal sign.

- 3x + 6(- 2x - 1) = 24

Simplify by using the distributive property.

- 3x + 6(- 2x) + 6(- 1) = 24
- 3x - 12x - 6 = 24.

Combine like terms

- 15x - 6 = 24

Add 6 to each side.

- 15x = 30

Divide both sides by - 15 to isolate variable X

x = 30 / - 15
x = - 2.

Now plug in the x-value we've found back into the first equation.

y = - 2( - 2) - 1
y = 4 - 1
y = 3

Your answer is (- 2, 3)

6 0

3 years ago