Mr. Jackson gave an exam worth 50 points.

The selling price of a house dropped from $250,000 to $210,000 over a period of 5 years.

AnnyKZ [126]

20% decreased and it needs to increase 40,000 more to get To its normal value

5 0

3 years ago

Would the scale factor 4.2 enlarge,reduce,or preserve

Juli2301 [7.4K]

Hey there! I'm happy to help!

Let's look at what scale factors would be able to enlarge, reduce, and preserve first. We will use the point (1,1) as an example.

ENLARGE

When we talk about scale factors, both of our numbers of the ordered pair will be multiplied by that number. To make it bigger, we will multiply it by anything larger than a one, we could have a scale factor such as 2, 100, 579395. etc.!

Dilation of 2

(1,1)⇒(2,2)

REDUCE

To reduce our ordered pair, our scale factor must be a number greater than zero but less than one because it cannot switch quadrants, which is what would happen if we used negative numbers. Our reduced number must be greater than zero. We can use 1/2, 1/4, 1/100, 0.67 etc.

Dilation of 1/2

(1,1)⇒(0.5,0.5)

PRESERVE

What would we multiply an ordered pair by to make it stay the same? One of course! This is the only number that will keep it the same!

Dilation of 1

(1,1)⇒(1,1)

Now, let's think of any scale factor as X and see what rules it has to follow to be enlarging, reducing, or preserving.

ENLARGING SCALE FACTOR: X>1

REDUCING SCALE FACTOR: 0<X<1

PRESERVING SCALE FACTOR: X=1

So, where does 4.2 fall? Well, as you can see, 4.2 is greater than one, so this scale factor would make our point larger.

Therefore, 4.2 would enlarge.

I hope that this helps! Have a wonderful day!

8 0

3 years ago

A medical researcher wondered if there is a significant difference between the mean birth weight of boy and girl babies. Random

Yuliya22 [10]

Answer:

b) independent samples t-test

$t=\frac{(5.92 -5.74)-(0)}{\sqrt{\frac{1.88^2}{5}}+\frac{1.81^2}{5}}=0.154$

$p_v =2*P(t_{8}>0.154) =0.881$

So with the p value obtained and using the significance level given $\alpha=0.05$ we have $p_v>\alpha$ so we can conclude that we have enough evidence to FAIL to reject the null hypothesis, and we can said that at 5% of significance the mean of the group 1 (boys) is NOT significantly different than the mean for the group 2 (Girls).

Step-by-step explanation:

The system of hypothesis on this case are:

Null hypothesis: $\mu_1 = \mu_2$

Alternative hypothesis: $\mu_1 \neq \mu_2$

Or equivalently:

Null hypothesis: $\mu_1 - \mu_2 = 0$

Alternative hypothesis: $\mu_1 -\mu_2\neq 0$

Our notation on this case :

$n_1 =5$ represent the sample size for group 1

$n_2 =5$ represent the sample size for group 2

We can calculate the mean and deviation for eaach group with the following formulas:

$\bar X= \frac{\sum_{i=1}^n X_i}{n}$

$s = \sqrt{\frac{\sum_{i=1}^n (X_i -\bar X)^2}{n-1}}$

$\bar X_1 =5.92$ represent the sample mean for the group 1

$\bar X_2 =5.74$ represent the sample mean for the group 2

$s_1=1.88$ represent the sample standard deviation for group 1

$s_2=1.81$ represent the sample standard deviation for group 2

If we see the alternative hypothesis we see that we are conducting a bilateral test and with independnet samples t test.

b) independent samples t-test

The statistic is given by this formula:

$t=\frac{(\bar X_1 -\bar X_2)-(\mu_{1}-\mu_2)}{\sqrt{\frac{s^2_1}{n_1}}+\frac{S^2_2}{n_2}}$

And now we can calculate the statistic:

$t=\frac{(5.92 -5.74)-(0)}{\sqrt{\frac{1.88^2}{5}}+\frac{1.81^2}{5}}=0.154$

The degrees of freedom are given by:

$df=5+5-2=8$

And now we can calculate the p value using the altenative hypothesis:

$p_v =2*P(t_{8}>0.154) =0.881$

So with the p value obtained and using the significance level given $\alpha=0.05$ we have $p_v>\alpha$ so we can conclude that we have enough evidence to FAIL to reject the null hypothesis, and we can said that at 5% of significance the mean of the group 1 (boys) is NOT significantly different than the mean for the group 2 (Girls).

7 0

3 years ago

Four more than a number is 27

son4ous [18]

Answer:

23 is the answer of the question

3 0

2 years ago

Read 2 more answers

A car drives 10 1/2 miles in 1/6 hour. what is its speed in miles per hour

EastWind [94]

(Credit to guy/girl above) 63 miles 10 1/2 x 6 is 63.

7 0

2 years ago