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According to a study conducted by the Toronto-based social media analytics firm Sysomos, of all tweets get no reaction. That is,

amm1812

Complete Question

According to a study conducted by the Toronto-based social media analytics firm Sysomos, 75% of all tweets get no reaction. That is, these are tweets that are not replied to or retweeted (Sysomos website, January ). Suppose we randomly select tweets.

a. What is the expected number of these tweets with no reaction (to the nearest whole number)?

b. What are the variance (to 2 decimals) and standard deviation (to 4 decimals) for the number of these tweets with no reaction? Variance Standard deviation

Answer:

a

The mean is $\mu = 150$

The variance $\sigma^2 =37.5$

The standard deviation is $\sigma \approx 6.1237$

Step-by-step explanation:

A binomial distribution is mathematically represented as $B(n,p)$

where n denotes the number of independent trials =200

And p denote the probability of success = 0.75

We also have the probability of failure which is denoted as q and is equivalent to $1-p$

if p and q are constant then

In binomial distribution the probability of x success and (n-x) is mathematically represented as

$P[X =x] =[\left n} \atop x}} \right. ] p^x (1-p)^{n-x}$

Where x= 0,1,2,...,n $for 0\le p \le 1$

Now $[\left n} \atop x}} \right. ] = \frac{n!}{x(n-x)!}$

Now the mean(Expected number ) of these probability in binomial distribution is mathematically represented as

$\mu = np$

$= 200 *0.75 = 150$

And the variance is mathematically represented as

$\sigma^2 = np(1-p)$

$= 200 * 0.75 (1-0.75) = 37.5$

And the standard deviation is mathematically represented as

$\sigma = \sqrt{np(1-p)}$

$= \sqrt{200 *0.75(1-0.75)} =\sqrt{37.5} \approx 6.1237$

We can obtain the standard z -score of a d

6 0

3 years ago

What would be the anwser

Digiron [165]

I think it’s C totally didn’t copy anybody

6 0

3 years ago

Choose the correct simplification of (3xy6)2(y3)3.

tigry1 [53]

The answer is 18xy^9, hope it helps.

5 0

4 years ago

Read 2 more answers

What is 2.75 rounded to the nearest hundredth

almond37 [142]

Well first off we need to know how to round or what rounding is. Rounding is the approximation of numbers usually decimals to a approximate cut off number for numbers that are too long or hard to work with/remember. To round a number you simply need to look at the number behind that number whether its a whole number (integer) or a decimal, either one will work. Now continuing on (on) how to round the number, look at the number after it and if it is 5 or above the number rounds up +1 and all numbers behind that turn to 0. For example 3.25500 round to the nearest hundredth, 3.26(000). Now if the number is 4 or smaller then you don't do anything at all (no rounding) and all the numbers after the being rounded number turn to 0's like so, 3.254(0000) rounded to the nearest hundredth, 3.25(00000). So now that we know how to round and what rounding is we need to look at are hundredth place on are number here and see what the next number is after that, in this case it is 0 because there is no stated number there the default next number is 0 like so,
2.750 and because 0 is under 5 we don't do any rounding at all here and just leave it as it is. So 2.75 rounded to the nearest hundredth is 2.75

Enjoy!=)

4 0

3 years ago

What is 36/192 simplified too

butalik [34]

The answer is 9/42. might be wrong I'm rusty on this.

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3 years ago