Assume that random guesses are made for nine multiple choice questions on an SAT test, so that there are nequals9 trials, each with probability of success (correct) given by pequals0.55. Find the indicated probability for the number of correct answers. Find the probability that the number x of correct answers is fewer than 4.

And adding we got:

Step-by-step explanation:

Let X the random variable of interest "number of correct answers", on this case we now that:

The probability mass function for the Binomial distribution is given as:

Where (nCx) means combinatory and it's given by this formula:

And we want to find this probability:

And we can find the individual probabilities:

And adding we got:

the answer is y < -3 or   y > 3

-3y > 7 + 2

-3 y > 9

y < -3

more detail

step-by-step explanation: