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2 years ago

Cassidy's diving platform is 6 ft above the water. One of her dives can

Mathematics

1 answer:

avanturin [10]2 years ago

8 0

Answer:

Before coming back up to the surface the maximum depth, Cassidy went was 6.25 ft. below the water surface

Step-by-step explanation:

The height of Cassidy's diving platform above the water = 6 ft.

The equation that models her dive is d = x² - 7·x + 6

Where;

d = Her vertical position or distance from the water surface

x = Here horizontal distance from the platform

At Cassidy's maximum depth, we have;

dd/dx = d(x² - 7·x + 6)/dx = 2·x - 7 = 0

x = 7/2 = 3.5

∴ At Cassidy's maximum depth, x = 3.5 ft.

The maximum depth, $d_{max}$ = d(3.5) = 3.5² - 7 × 3.5 + 6 = -6.25

The maximum depth, Cassidy went before coming back up to the surface = $d_{max}$ = -6.25 ft = 6.25 ft. below the surface of the water.

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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:

$p_v =P(t_{130}$

5 0

3 years ago

14.

romanna [79]

1. C
2.D
3.A
4.B
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5 0

3 years ago

Provide a solution for the following equation: 3x + 2y=4

shtirl [24]

Answer:

One solution is to find x and y by doing the following:

Step-by-step explanation:

Let's solve for x.

3x+2y=4

Step 1: Add -2y to both sides.

3x+2y+−2y=4+−2y

3x=−2y+4

Step 2: Divide both sides by 3.

x=-2/3y+4/3

Lets solve for y.

3x+2y=4

Step 1: Add -3x to both sides.

3x+2y+−3x=4+−3x

2y=−3x+4

Step 2: Divide both sides by 2.

y= -3/2x+2

7 0

3 years ago

Given square PQRS, determine the missing information.

Julli [10]

Answer:

Step-by-step explanation:

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2 years ago

(4.23)(1.6) please multiple

Wewaii [24]

Answer:

The correct answer is 6.768.

Step-by-step explanation:

(4.23)(1.6) = 6.768

8 0

3 years ago

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