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algol13
3 years ago
14

A study of the amount of time it takes a mechanic to rebuild the transmission for a 2005 Chevrolet Cavalier shows that the mean

is 8.4 hours and the standard deviation is 1.8 hours. If 40 mechanics are randomly selected, find the probability that their mean rebuild time exceeds 8.7 hours.
0.1346

0.1285

0.1946

0.1469
Mathematics
1 answer:
iogann1982 [59]3 years ago
3 0

Answer:

0.1469

Step-by-step explanation:

Given from the question;

Mean=8.4 hrs=μ

Standard deviation=1.8 hrs=δ

Sample size, n=40

Let  x=8.7

z=(x-μ)÷(δ÷√n)  

Find z(8.7)

z=(8.7-8.4)÷(1.8÷√40)

z={0.3×√40}÷1.8=1.05409

z=1.0541

Read from the  standard normal probabilities table

P(z>1.0541)

=0.1459

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I was wondering if someone would help me with some show your work questions...
adell [148]

Answer:

5/6

Step-by-step explanation:

to add fractions they need to have a common denominator

make 1/3 have a denominator of 18

1/3(6) = 6/18

9/18 + 6/18 = 15/18

15/18 can be simplified to 5/6

4 0
3 years ago
What is the GCF of <br><br> 2X^3+3X^2+8X+12
tia_tia [17]

Answer:

The GFC is 1

Step-by-step explanation:

5 0
2 years ago
A poll reported that 66% of adults were satisfied with the job the major airlines were doing. Suppose 20 adults are selected at
NARA [144]

Answer:

0.5640

Step-by-step explanation:

n = 12 (number of adults)

p = 0.65 (probability that an adult is satisfied with the job the major airlines were doing.

x = number of adults out of 11 who were satisfied.

a)

P( x = 5) = 11C5 (0.65)^5 (0.35)^6 = 0.0986

b)

P( x < 3) = P(x=0)+P(x=1)+P(x=2)

P( x =0) = 11C0 (0.65)^0 (0.35)^11 = 0.0000

P( x =1) = 11C1 (0.65)^1 (0.35)^10 = 0.0002

P( x =2) = 11C2 (0.65)^2 (0.35)^9 = 0.0018

Add: P( x < 3) = 0.0020

c)

P( x ≥ 8) = P(x=8)+P(x=9)+P(x=10)+P(x=11)

P( x =8) = 11C8 (0.65)^8 (0.35)^3 = 0.2254

P( x =9) = 11C9 (0.65)^9 (0.35)^2 = 0.1395

P( x =10) = 11C10 (0.65)^10 (0.35)^1 = 0.0518

P( x =11) = 11C11 (0.65)^11 (0.35)^0 = 0.0087

add:

P( x ≥ 8) = 0.4254

d)

P(x=4)+P(x=5)+P(x=6)+P(x=7)

P( x =4) = 11C4 (0.65)^4 (0.35)^7 = 0.0379

P( x =5) = 11C5 (0.65)^5 (0.35)^6 = 0.0985

P( x =6) = 11C6 (0.65)^6 (0.35)^5 = 0.1830

P( x =7) = 11C7 (0.65)^7 (0.35)^4 = 0.2428

Add: 0.5640

8 0
3 years ago
Help! which one is it? I'm confused! :(
disa [49]

Answer:

its D

Step-by-step explanation:

x+2x=90-45

3x=45

6 0
2 years ago
Read 2 more answers
Please answer both questions.
mario62 [17]

Answer:

1) (x-6)^2=49

2) C

Step-by-step explanation:

Subtract 12 x and you get

-x^2-12x+13=0

You will be left with, after making a perfect square

(x-6)^2=49

To get rid of the squared/2nd power, add plus or minus to the opposite side and square root both sides. You will be left with

x-6=plus or minus 7

Your answer comes out to the to problem. Setting both to 0, you get -13, and 1. -6 plus 7 is 1, and -6 plus a -7 is -13.

6 0
1 year ago
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