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3 years ago

Please help and if you dont know please don't answer

Mathematics

2 answers:

quester [9]3 years ago

8 0

The answer is 81 centimeters

Allisa [31]3 years ago

5 0

Answer:

81cm

Step-by-step explanation:

15cm + 20cm + 21cm + 25cm = 81cm

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A random sample of 10 parking meters in a resort community showed the following incomes for a day. Assume the incomes are normal

GenaCL600 [577]

Answer:

A 95% confidence interval for the true mean is [$3.39, $6.01].

Step-by-step explanation:

We are given that a random sample of 10 parking meters in a resort community showed the following incomes for a day;

Incomes (X): $3.60, $4.50, $2.80, $6.30, $2.60, $5.20, $6.75, $4.25, $8.00, $3.00.

Firstly, the pivotal quantity for finding the confidence interval for the population mean is given by;

P.Q. = $\frac{\bar X-\mu}{\frac{s}{\sqrt{n} } }$ ~ $t_n_-_1$

where, $\bar X$ = sample mean income = $\frac{\sum X}{n}$ = $4.70

s = sample standard deviation = $\sqrt{\frac{\sum (X-\bar X)^{2} }{n-1} }$ = $1.83

n = sample of parking meters = 10

$\mu$ = population mean

Here for constructing a 95% confidence interval we have used a One-sample t-test statistics because we don't know about population standard deviation.

So, 95% confidence interval for the population mean, $\mu$ is ;

P(-2.262 < $t_9$ < 2.262) = 0.95 {As the critical value of t at 9 degrees of

freedom are -2.262 & 2.262 with P = 2.5%}

P(-2.262 < $\frac{\bar X-\mu}{\frac{s}{\sqrt{n} } }$ < 2.262) = 0.95

P( $-2.262 \times {\frac{s}{\sqrt{n} } }$ < ${\bar X-\mu$ < $2.262 \times {\frac{s}{\sqrt{n} } }$ ) = 0.95

P( $\bar X-2.262 \times {\frac{s}{\sqrt{n} } }$ < $\mu$ < $\bar X+2.262 \times {\frac{s}{\sqrt{n} } }$ ) = 0.95

95% confidence interval for $\mu$ = [ $\bar X-2.262 \times {\frac{s}{\sqrt{n} } }$ , $\bar X+2.262 \times {\frac{s}{\sqrt{n} } }$ ]

= [ $4.70-2.262 \times {\frac{1.83}{\sqrt{10} } }$ , $4.70+ 2.262 \times {\frac{1.83}{\sqrt{10} } }$ ]

= [$3.39, $6.01]

Therefore, a 95% confidence interval for the true mean is [$3.39, $6.01].

The interpretation of the above result is that we are 95% confident that the true mean will lie between incomes of $3.39 and $6.01.

Also, the margin of error = $2.262 \times {\frac{s}{\sqrt{n} } }$

= $2.262 \times {\frac{1.83}{\sqrt{10} } }$ = 1.31

4 0

3 years ago

Round the following 8.388 to 2 decimal places

Roman55 [17]

The answer will be 8.39 because the third number (8) is above 5 so you have to round up. Good luck!

3 0

3 years ago

Shaun needs to make mortar for brick-laying. It is made in the ratio 7:3 of sand to cement.

Tju [1.3M]

Sand to cement
7:3

210:x

ask yourself what number is needed to multiply by 7 to get 210 ( so you'd divide 210 by 7 which is 30). Multiply the other side by thirty as well to get the value of x

3*30 which is 90

7 0

3 years ago

Foster makes sandwiches at a deli. There are 8 1/2 (eight and one half) pounds of turkey at the deli. How many 1/4 (one fourth)p

atroni [7]

foster can make 42 1/4-pound turkey sandwiches

explanation: 10.5 divided by 1/4 is 42

4 0

3 years ago

1. Which graph models the equation y = 3.5x?

MAXImum [283]

1) is C because the line is increasing not decreasing and it goes up 7 & right 2.
2) the y-intercept is -2 and the slope is up 3 over 1, so the answer has to be B
3) the answer is A because the up 2 over 3
4) the y-intercept is a positive 4, and the slope is going down 3 and to the right 5, and the line is decreasing so you know it has to be negative. the answer is D

7 0

3 years ago