If a baseball player has a batting average of 0.275, what is

zakinutuzi

zakinutuzi

Answered question

2021-12-18

If a baseball player has a batting average of 0.275, what is the likelihood that the player will get the following number of hits in the next four times at bat?
(A) Exactly 2 hits 
(B) At least 2 hits 
(A) P(exactly 2 hits) .029 (Round to three decimal places as needed.)

Answer & Explanation

nghodlokl

nghodlokl

Beginner2021-12-19Added 33 answers

Step 1
Introduction:
Denote X as the random variable representing the number of hits made by the player in the next 4 times at bat.
Step 2
A. Consider that the player hits or misses each of the next 4 times at bat, independently of each other. Further, consider it to be a success if the player makes a hit.
As the batting average is 0.275, the probability of “success” is p=0.275.
Here, X can be considered as the number of successes observed among the 4 times at bat. Thus, it may be assumed that, X has a binomial distribution with parameters, n=4,p=0.275.
Since p denotes the probability of success, the probability of failure is, q=1-p=0.725.
If X~Binomialn,p, then the probability mass function of X is:
f(x)={(nx)pxqnx;x=0,1,...,n;&0 Here, n is the number of independent trials, p is the probability of success in each trial, and q is the probability of failure.
The probability mass function of X here is:
f(x)={(4x)(0.275)x(0.725)4x;x=0,1,2,3,4.0;otherwise
The probability that the player will get exactly 2 hits, that is, PX=2 is calculated below:
PX=2=f2
=(42)(0.275)2(0.725)42
=6·0.075625·0.525625
0.239.
Thus, the probability that the player will get exactly 2 hits is 0.239.
Step 3
B. The probability that the player will get at least 2 hits, that is, PX2 is calculated below:
PX2=f2+f3+f4
=(42)(0.275)2(0.725)42+(43)(0.275)3(0.725)43+(44)(0.275)4(0.725)44
((6)(0.075626)(0.525625)+(4)(0.020797)(0.725)+(1)(0.2754)(1)
0.238502+0.060311+0.005719
0.305.
Thus, the probability that the player will get at least 2 hits is 0.305.

Jim Hunt

Jim Hunt

Beginner2021-12-20Added 45 answers

Step 1
Here we are given XBinomial(μ, 0.215)
so we are to find
a) P(x=2)=4cx(0.275)2(0.725)2=0.2385
b) P(x2)=1x=024cx(0.275)x(0.725)4x
=0.5808
as P(x=x)=ncx+x(1p)nx
nick1337

nick1337

Expert2021-12-28Added 777 answers

Step 1
Let X the random variable of interest, on this case we now that:
XBinom(n=4, p=0.375)
The probability mass function for the Binomial distribution is given as:
P(X)=(nCx)(p)x(1p)nx
Where (nCx) means combinatory and it's given by this formula:
nCx=n!(nx)!x!
Part a
P(X=2)=(4C2)(0.375)2(10.375)42=0.330
Part b
P(X2)=1P(X<2)=1[P(X=0)+P(X=1)]
P(X=0)=(4C0)(0.375)0(10.375)40=0.153
P(X=1)=(4C1)(0.375)1(10.375)41=0.366
And replacing we got:
P(X2)=1P(X<2)=1[0.153+0.3660=0.481

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