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2 years ago

How to do this question plz answer

Mathematics

2 answers:

harina [27]2 years ago

5 0

9514 1404 393

Answer:

300

Step-by-step explanation:

There are 25 ways to select the first student. After that student is removed from the selection pool for the second student, there are 24 ways to select the second student. This gives 25·24 = 600 ways to select 2 students in a particular order.

Since we don't care about the order, we can divide this number by the number of ways two students can be ordered: AB or BA, 2 ways.

600/2 = 300

There are 300 ways to pick a combination of two students from 25.

Additional comments

This sort of selection (2 out of 25) has a formula for it, and an abbreviation for the formula.

"n choose k" can be written nCk or C(n, k)

The function is a ratio of factorials:

nCk = n!/(k!(n-k)!)

If you can typeset this, it is written ...

$\displaystyle\binom{n}{k}=\frac{n!}{k!\cdot(n-k)!}$

This is different from the formula for the number of permutations of n things taken k at a time. That would be written nPk or P(n, k) = n!/(n-k)!.

Ivahew [28]2 years ago

5 0

Answer:

300

Step-by-step explanation:

600 / 2 = 300

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Consider a chemical company that wishes to determine whether a new catalyst, catalyst XA-100, changes the mean hourly yield of i

kolezko [41]

Answer:

Null hypothesis: $\mu = 750$

Alternative hypothesis: $\mu \neq 750$

$t=\frac{811-750}{\frac{19.647}{\sqrt{5}}}=6.943$

$p_v =2*P(t_{4}>6.943)=0.00226$

If we compare the p value and a significance level assumed $\alpha=0.05$ we see that $p_v$ so we can conclude that we reject the null hypothesis, and the actual true mean is significantly different from 750 pounds per hour.

Step-by-step explanation:

Data given and notation

Data: 801, 814, 784, 836,820

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

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

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

$\bar X=811$ represent the sample mean

$s=19.647$ represent the standard deviation for the sample

$n=5$ sample size

$\mu_o =750$ represent the value that we want to test

$\alpha$ 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 to be tested

We need to conduct a hypothesis in order to determine if the mean is different from 750 pounds per hour, the system of hypothesis would be:

Null hypothesis: $\mu = 750$

Alternative hypothesis: $\mu \neq 750$

Compute the test statistic

We don't know the population deviation, so for this case is better apply a t test to compare the actual mean to the reference value, and the statistic is given by:

$t=\frac{\bar X-\mu_o}{\frac{s}{\sqrt{n}}}$ (1)

t-test: "Is used to compare group means. Is one of the most common tests and is used to determine if the mean is (higher, less or not equal) to an specified value".

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

$t=\frac{811-750}{\frac{19.647}{\sqrt{5}}}=6.943$

Now we need to find the degrees of freedom for the t distirbution given by:

$df=n-1=5-1=4$

What do you conclude?

Compute the p-value

Since is a two tailed test the p value would be:

$p_v =2*P(t_{4}>6.943)=0.00226$

4 0

3 years ago

In ΔMNO, m = 780 inches, o = 760 inches and ∠O=164°. Find all possible values of ∠M, to the nearest degree.

Mademuasel [1]

Answer:

So the answer is both

180 and 328 (but it may or may not show you "not possible, if so, then you got it right)

Step-by-step explanation:

SinA/a= SinB/b

1. SinM/780 = Sin164/760

2. 780sin164/760 = 0.2828909704

3. M = sin^-1 (0.2828909704)= 16.4328229 or 16

Check for possibility

180-16= 164

164 + 16= 180 (not possible)

164 + 164= 328 (not possible)

4 0

3 years ago

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shusha [124]

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3 years ago

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Julie baked cupcakes for her family at home and for a party at school. She iced 4 cupcakes with red frosting, 2 cupcakes with or

bonufazy [111]

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8 0

3 years ago

Help me please!!!!!!

maks197457 [2]

To find the median, find the middle number. Since there are 10 numbers, find the 5th one and the 6th one and find their average.

The two numbers are both 9, so its safe to say that the median is 9.

to find the median of the first and quartile, you have to place a line where the median should be and find the median of that. Q1 and Q2 will be 5 and 11 (respectively).

Its easy to see that all the lines start at the lowest point given and end at the largest point given, so match Q1, the median, and Q3

The only line that has lines at the Q1, median, and Q3 we figured out is answer C, so therefore it is the answer.

8 0

3 years ago

How to do this question plz answer ​

How to do this question plz answer