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3 years ago

Need help with 4, thanks!

Mathematics

1 answer:

Veseljchak [2.6K]3 years ago

7 0

Answer:

x=2

Step-by-step explanation:

In order to solve this problem, you need to find the scale factor. This is done through cross multiplying proportions. In this instance, you have to cross multiply x/4 by 3.5/7. When you multiply x and 7, you get 7x. When you multiply 3.5 and 4, you get 14. Simplify by isolating the variable, and you get 2.

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the cost to operate a certain aircraft is $255 per hour the algebraic expression 255t gives the total cost to operate the aircra

Temka [501]

Answer:

Total cost for 2.80 hours = ($255/hr)(2.80 hrs) = $714.

Step-by-step explanation:

Multiply this hourly rate by the elapsed time (2.80 hours):

Total cost for 2.80 hours = ($255/hr)(2.80 hrs) = $714.

3 0

2 years ago

A university wants to compare out-of-state applicants' mean SAT math scores (?1) to in-state applicants' mean SAT math scores (?

nordsb [41]

Answer:

d. Yes, because the confidence interval does not contain zero.

Step-by-step explanation:

We are given that the university looks at 35 in-state applicants and 35 out-of-state applicants. The mean SAT math score for in-state applicants was 540, with a standard deviation of 20.

The mean SAT math score for out-of-state applicants was 555, with a standard deviation of 25.

Firstly, the Pivotal quantity for 95% confidence interval for the difference between the population means is given by;

P.Q. = $\frac{(\bar X_1-\bar X_2)-(\mu_1-\mu_2)}{s_p\sqrt{\frac{1}{n_1} +\frac{1}{n_2} } }$ ~ $t__n__1-_n__2-2$

where, $\bar X_1$ = sample mean SAT math score for in-state applicants = 540

$\bar X_2$ = sample mean SAT math score for out-of-state applicants = 555

$s_1$ = sample standard deviation for in-state applicants = 20

$s_2$ = sample standard deviation for out-of-state applicants = 25

$n_1$ = sample of in-state applicants = 35

$n_2$ = sample of out-of-state applicants = 35

Also, $s_p=\sqrt{\frac{(n_1-1)s_1^{2} +(n_2-1)s_2^{2} }{n_1+n_2-2} }$ = $\sqrt{\frac{(35-1)\times 20^{2} +(35-1)\times 25^{2} }{35+35-2} }$ = 22.64

<em>Here for constructing 95% confidence interval we have used Two-sample t test statistics.</em>

So, 95% confidence interval for the difference between population means ( $\mu_1-\mu_2$ ) is ;

P(-1.997 < $t_6_8$ < 1.997) = 0.95 {As the critical value of t at 68 degree

of freedom are -1.997 & 1.997 with P = 2.5%}

P(-1.997 < $\frac{(\bar X_1-\bar X_2)-(\mu_1-\mu_2)}{s_p\sqrt{\frac{1}{n_1} +\frac{1}{n_2} } }$ < 1.997) = 0.95

P( $-1.997 \times {s_p\sqrt{\frac{1}{n_1} +\frac{1}{n_2} } }$ < ${(\bar X_1-\bar X_2)-(\mu_1-\mu_2)}$ < $1.997 \times {s_p\sqrt{\frac{1}{n_1} +\frac{1}{n_2} } }$ ) = 0.95

P( $(\bar X_1-\bar X_2)-1.997 \times {s_p\sqrt{\frac{1}{n_1} +\frac{1}{n_2} } }$ < ( $\mu_1-\mu_2$ ) < $(\bar X_1-\bar X_2)+1.997 \times {s_p\sqrt{\frac{1}{n_1} +\frac{1}{n_2} } }$ ) = 0.95

<u>95% confidence interval for</u> ( $\mu_1-\mu_2$ ) =

[ $(\bar X_1-\bar X_2)-1.997 \times {s_p\sqrt{\frac{1}{n_1} +\frac{1}{n_2} } }$ , $(\bar X_1-\bar X_2)+1.997 \times {s_p\sqrt{\frac{1}{n_1} +\frac{1}{n_2} } }$ ]

=[ $(540-555)-1.997 \times {22.64 \times \sqrt{\frac{1}{35} +\frac{1}{35} } }$ , $(540-555)+1.997 \times {22.64 \times \sqrt{\frac{1}{35} +\frac{1}{35} } }$ ]

= [-25.81 , -4.19]

Therefore, 95% confidence interval for the difference between population means SAT math score for in-state and out-of-state applicants is [-25.81 , -4.19].

This means that the mean SAT math scores for in-state students and out-of-state students differ because the confidence interval does not contain zero.

So, option d is correct as Yes, because the confidence interval does not contain zero.

6 0

3 years ago

What is the length of the transverse axis?

taurus [48]

Answer:

Hope this helps :)

Step-by-step explanation:

3 0

3 years ago

Help me please i need help

adell [148]

Answer:

I have NO IDEA

Step-by-step explanation:

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8 0

2 years ago

What is 15% of 287? Calculate the percentages. Make sure to show all your work!

jolli1 [7]

Answer:

Step-by-step explanation:15 percent *287 = (15/100)*287 = (15*287)/100 = 4305/100 = 43.05Now we have: 15 percent of 287 = 43.05Question: What is 15 percent of 287?We need to determine 15% of 287 now and the procedure explaining it as suchStep 1: In the given case Output Value is 287.Step 2: Let us consider the unknown value as x.Step 3: Consider the output value of 287 = 100%.Step 4: In the Same way, x = 15%.Step 5: On dividing the pair of simple equations we got the equation as under287 = 100% (1).x = 15% (2).(287%)/(x%) = 100/15Step 6: Reciprocal of both the sides results in the following equationx%/287% = 15/100Step 7: Simplifying the above obtained equation further will tell what is 15% of 287x = 43.05%Therefore, 15% of 287 is 43.05

6 0

1 year ago

Read 2 more answers