the number of calls received by an office on Monday morning between 8:00am and 9:30 am has a mean of 3.Calculate the probability of getting no more than 3 calls between eight and nine in the morning.

Step-bLet X be the number of calls received by an office on Monday morning between 8:00 AM and 9:00 AM.

In mathematical terms,  

X

∼

P

o

i

s

s

o

n

(

2

)

.

The PMF of the random variable X is given as,

P

(

X

=

x

)

=

e

−

2

×

2

x

x

!

f

o

r

x

=

0

,

1

,

2

,

.

.

.

.

.

=

0

E

l

s

e

w

h

e

r

e

The probability of getting no more than 3 calls between eight and nine in the morning is obtained by the following way,

P

(

X

≤

3

)

=

P

(

X

=

0

)

+

P

(

X

=

1

)

+

P

(

X

=

2

)

+

P

(

X

=

3

)

=

e

−

2

×

2

0

0

!

+

e

−

2

×

2

1

1

!

+

e

−

2

×

2

2

2

!

+

e

−

2

×

2

3

3

!

=

0

.13534

+

0

.27067

+

0

.27067

+

0

.18045

=

0

.85712

Hence the probability of getting no more than 3 calls between eight and nine in the morning is 0.85712.y-step explanation:

16

step-by-step explanation:

look at the picture.

y-intercept for the function on a picture is 4 → point (0, 4).

y-intercept for the function

is for x = 0. substitute:

y-intercept is 8 → point (0, 8).