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3 years ago

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Keisha ran to swim practice but needed to stop by her friend Natasha’s house on the way. She stayed at Natasha’s house for 15 mi

nutes, and together they ran the rest of the way to practice, where they stayed for 1 hour.
Which graph best represents the scenario described?

1 answer:

Nadusha1986 [10]3 years ago

7 0

The answers would be C. the straight horizontal lines represent when she is(not moving) stationary

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A Statistics professor has observed that for several years students score an average of 106 points out of 150 on the semester ex

tekilochka [14]

Answer:

Step-by-step explanation:

We would set up the hypothesis test. This is a test of a single population mean since we are dealing with mean

For the null hypothesis,

µ = 106

For the alternative hypothesis,

µ > 106

It is a right tailed test because of >.

Since no population standard deviation is given, the distribution is a student's t.

Since n = 241,

Degrees of freedom, df = n - 1 = 241 - 1 = 240

t = (x - µ)/(s/√n)

Where

x = sample mean = 109

µ = population mean = 106

s = samples standard deviation = 8.3

a) test statistic, t = (109 - 106)/(8.3/√241) = 5.61

We would determine the p value using the t test calculator. It becomes

p = 0.00001

Since alpha, 0.05 > than the p value, 0.00001, then we would reject the null hypothesis. Therefore, At a 5% level of significance, this improvement seem to be practicallysignificant.

b) Confidence interval is written in the form,

(Sample mean - margin of error, sample mean + margin of error)

The sample mean, x is the point estimate for the population mean.

Margin of error = z × s/√n

Where

s = sample standard deviation

n = number of samples

From the information given, the population standard deviation is unknown, hence, we would use the t distribution to find the z score

df = 240

Since confidence level = 95% = 0.95, α = 1 - CL = 1 – 0.95 = 0.05

α/2 = 0.05/2 = 0.025

the area to the right of z0.025 is 0.025 and the area to the left of z0.025 is 1 - 0.025 = 0.975

Looking at the t distribution table,

z = 1.6512

Margin of error = 1.6512 × 8.3/√241

= 0.88

Confidence interval = 109 ± 0.88

7 0

3 years ago

Find the sum of first 20 to terms of an ap in which d is equal to 7 and 20 second term is 149

GuDViN [60]

Answer:

1370

Step-by-step explanation:

<h3>Given</h3>

AP with d= 7 and a₂₂ = 149

<h3>To find</h3>

Sum of first 20 terms

<h3>Solution</h3>

<u>First, let's get the value of the first term:</u>

aₙ = a + (n-1)d
a₂₂ = a + 21d
149 = a + 21*7
a = 149 - 147
a= 2

<u>Next, let's find the sum of the first 20 terms</u>

Sₙ = 1/2n(2a+ (n-1)d)
S₂₀ = 1/2*20(2*2 + 19*7) = 10(4 + 133) = 10*137 = 1370

<u>Answer is</u> 1370

6 0

3 years ago

Read 2 more answers

If f(x)=2x-4, what would be the answer if f(3)-1??

Vinil7 [7]

Answer:

1

Step-by-step explanation:

We have the function

$f(x) = 2x - 4$

and we want to know the value of $f(3) - 1$ .

The first step is to find $f(3)$ ; we can subtract 1 from it at the end! But what does $f(3)$ mean?

Basically, we're saying <em>"what is the value of the function when </em> $x = 3$ <em> ?"</em>

So, we simply replace $x$ with 3 in the function, and we get:

$f(3) = 2\times 3 - 4 = 2$ .

Finally, we subtract 1 to find $f(3) - 1 = 1$ .

3 0

3 years ago

Let g be the function given by g(x)=x^2*e^(kx) , where k is a constant. For what value of k does g have a critical point at x=2/

ArbitrLikvidat [17]

G `( x ) = $2x * e^{kx} + k x^{2} *e^{kx} = \\ = xe^{kx}(2 + kx )$
2 + k x = 0
k x = -2
k = -2: x = - 2 : 2/3 = - 2 * 3/2
k = - 3
Answer: for k= - 3, the function g ( x ) have a critical point at x = 2/3.

8 0

3 years ago

Describe the transformation from the graph of f(x) = x + 2 to the graph of g(x) = x − 7.

galina1969 [7]

The graph went down 9

7 0

3 years ago