One crate can hold 8 cases of trading cards.How many crates are needed to hold 128 cases of trading cards?

If molly walks 4 miles in 70 minutes, then molly will walk how far in 100 minutes if she walks at the same speed the whole time?

barxatty [35]

Find out how far Molly walks in 1 minute.

4/70 = 0.057 miles
In 100 minutes,
0.057x100 = 5.714 miles

Rounded to the nearest tenth, 5.7 miles.

Hope I helped :)

7 0

3 years ago

In a study of the stability of IQ scores, a large group of individuals is tested once at age 18 and again at age 35. The followi

Naddika [18.5K]

Answer:

112

Step-by-step explanation:

Given that in a study of the stability of IQ scores, a large group of individuals is tested once at age 18 and again at age 35.

Age 18: average score = 100, SD = 15

Age 35: average score = 100, SD = 15, r = 0.80

Let us obtain regression equation of y on x.

Let y be the scores at age 35 and x at age 18

Slope = $r(s_y/s_x) = 0.8(\frac{15}{15} )=0.80$

The line passes through (100,100) being average of x and y

Hence regression line would be

$y-100=0.8(x-100)\\y = 0.8x+20$

a) Here given that x =115

Hence $y=0.80(115)+20\\=112$

the average score at age 35 for all the individuals who scored 115 at age 18, would be 112.

b) Prediction also would be the same 112.

5 0

3 years ago

To compare two programs for training industrial workers to perform a skilled job, 20 workers are included in an experiment. Of t

nikklg [1K]

Answer:

$t=\frac{19.1-23.3}{\sqrt{\frac{4.818^2}{10}+\frac{5.559^2}{10}}}}=-1.805$

$p_v =P(t_{(18)}$

If we compare the p value and the significance level assumed $\alpha=0.05$ we see that $p_v$ so we can conclude that we have enough evidence to reject the null hypothesis, and we can conclude the the true mean for method 1 is lower than the mean for the method 2 at 5% of significance

Step-by-step explanation:

Data given and notation

We can calculate the sample mean and deviation with these formulas:

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

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

$\bar X_{1}=19.1$ represent the mean for the sample mean for 1

$\bar X_{2}=23.3$ represent the mean for the sample mean for 2

$s_{1}=4.818$ represent the sample standard deviation for the sample 1

$s_{2}=5.559$ represent the sample standard deviation for the sample 2

$n_{1}=10$ sample size selected 1

$n_{2}=10$ sample size selected 2

$\alpha$ represent the significance level for the hypothesis test.

t would represent the statistic (variable of interest)

$p_v$ represent the p value for the test (variable of interest)

State the null and alternative hypotheses.

We need to conduct a hypothesis in order to check if the average time taken when training under method 1 is less than the average time for Method 2, the system of hypothesis would be:

Null hypothesis: $\mu_{1} \geq \mu_{2}$

Alternative hypothesis: $\mu_{1} < \mu_{2}$

If we analyze the size for the samples both are less than 30 so for this case is better apply a t test to compare means, and the statistic is given by:

$t=\frac{\bar X_{1}-\bar X_{2}}{\sqrt{\frac{s^2_{1}}{n_{1}}+\frac{s^2_{2}}{n_{2}}}}$ (1)

t-test: "Is used to compare group means. Is one of the most common tests and is used to determine whether the means of two groups are equal to each other".

Calculate the statistic

We can replace in formula (1) the info given like this:

$t=\frac{19.1-23.3}{\sqrt{\frac{4.818^2}{10}+\frac{5.559^2}{10}}}}=-1.805$

P-value

The first step is calculate the degrees of freedom, on this case:

$df=n_{1}+n_{2}-2=10+10-2=18$

Since is a one sided test the p value would be:

$p_v =P(t_{(18)}$

Conclusion

If we compare the p value and the significance level assumed $\alpha=0.05$ we see that $p_v$ so we can conclude that we have enough evidence to reject the null hypothesis, and we can conclude the the true mean for method 1 is lower than the mean for the method 2 at 5% of significance

4 0

3 years ago

A trapezoid has a height of 6 feet. The measures of the bases are 12 units and 18

Alik [6]

The area of this trapezoid is 90 square feet.

<h3>Explanation : </h3>

Before we know the answer, let's we know the formula first. The formula for count the area of trapezoid is :

$\boxed {\bold {A = \frac {(a+b) \times h}{2}}}$

If :

A = area of trapezoid
a = bottom bases of trapezoid
b = top bases of trapezoid
h = height of trapezoid

Okay, let's we count its :

We know that :

a = bottom bases of trapezoid = 18 feet
b = top bases of trapezoid = 12 feet
h = height of trapezoid = 6 feet

Question : A = area = ... ?

Answer :

$A = \frac {(a+b) \times h}{2} \\ A = \frac {(12+18) \times \cancel6}{\cancel2} \\ A = 30 \times 3 = 90 \: {ft}^{2}$

Subject : Mathematics

Keyword : Count The Area of a shape

8 0

3 years ago

Terminos semejantes de -7a²(4a-3)

barxatty [35]

Answer:

Yahshbsjjskskkqkosld

8 0

3 years ago