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3 years ago

PLEASE HELP..MATH 8TH GRADE

Mathematics

2 answers:

jolli1 [7]3 years ago

8 0

Answer. z = ± √10 = ± 3.1623

Dmitriy789 [7]3 years ago

4 0

Z = -16 the steps are in the photo

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A random sample of 240 adults over the age of 40 found that 144 would use an online dating service. Another random sample of 234

d1i1m1o1n [39]

The options at the end of the question are not typed properly, the correct options are given below.

A. √[144/240(1−144/240)/240] + [131/234(1−131/234)/234]

B. 1.65√[144/240(1−144/240)/240] + [131/234(1−131/234)/234]

C. 1.96√[144/240(1−144/240)/240] + [131/234(1−131/234)/234]

D. √[275/474(1−275/474)/474] + [275/474(1−275/474)/474]

E. 1.65√[275/474(1−275/474)/474] + [275/474(1−275/474)/474]

Given Information:

Confidence interval = 90%

Sample size of adults over the age of 40 = n₁ = 240

Sample size of adults under the age of 40 = n₂ = 234

Number of adults over the age of 40 who would use an online dating service = 144

Number of adults under the age of 40 who would use an online dating service = 131

Required Information:

standard error = ?

Answer:

standard error = 0.075

Step-by-step explanation:

The population proportion of adults over the age of 40 who would use an online dating service is,

p₁ = 144/240

p₁ = 0.6

The population proportion of adults under the age of 40 who would use an online dating service is,

p₂ = 131/234

p₂ = 0.56

The Standard Error is given by

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

Where z is the corresponding z-score value for the 90% confidence level that is 1.65

SE = 1.65*√(0.6(1 - 0.6)/240 + 0.56(1 - 0.56)/234)

This is the equation corresponding to the correct option B given in the question.

SE = 1.65*0.0453

SE = 0.075

Therefore, 0.075 is the standard error for 90% confidence interval to estimate the difference between the population proportions of adults within each age group who would use an online dating service.

8 0

3 years ago

Taxi Fares are normally distributed with a mean fare of $22.27 and a standard deviation of $2.20.

Novosadov [1.4K]

Answer:

Step-by-step explanation:

Given that taxi Fares are normally distributed with a mean fare of $22.27 and a standard deviation of $2.20.

For a random single taxi std deviation is 2.20

But for a sample of size 10, std deviation would be

$\frac{2.20}{\sqrt{10} }$

This would be less than the 2.20

Because std devition is less for sample we get a big z score for the sample than the single.

As positive values of z increase we find that probability would decrease since normal curve is bell shaped.

So single taxi fare would have higher probability than sample.

B) Here >24.

By the same argument we have z value less for single taxi hence the probability for more than that would be less than that of sample size 10

3 0

2 years ago

If john is twice as old as mark and john's age plus marks age is 36, then how old is mark

saw5 [17]

John would e 24 and mark would be 12

7 0

3 years ago

Read 2 more answers

How to find the percent of 0.89

jonny [76]

So basically, you would have to do 89/100, and 89/100 is 89%

8 0

2 years ago

Read 2 more answers

If f(x)=3x+2, what is f(5)

patriot [66]

Answer:

Step-by-step explanation:

f(x)=3x+2

To find f (5) replace every x in f(x) by 5

That's

f(5) = 3(5) + 2

= 15 + 2

Hope this helps you

5 0

3 years ago

PLEASE HELP..MATH 8TH GRADE​

PLEASE HELP..MATH 8TH GRADE