According to a study conducted by the Toronto-based social media analytics firm Sysomos, 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

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

a

The mean is  

The variance

The standard deviation is

Step-by-step explanation:

A binomial distribution is mathematically represented as

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

if p and q are constant then

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

Where x= 0,1,2,...,n

Now

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

And the variance is mathematically represented as

And the standard deviation is mathematically represented as

We can obtain the standard z -score of a d

it is a. 4.2 because 7.6-3.4 gets the remaining length of 4.2. i might be wrong but i am pretty sure this is the answer.