the mean speed of vehicles on a stretch of I-84 is 69/5 mph, with a standard deviation of 4 mph. A random sample of 64 vehicles is selected. Find the probabilty that the mean speed is 70 mph

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Complete Question

The mean speed of vehicles on a stretch of I-84 is 69.5 mph, with a standard deviation of 4 mph. A random sample of 64 vehicles is selected. Find the probabilty that the mean speed is 70 mph

0.84134

Step-by-step explanation:

When given a random number of samples when asked to find probability of that a mean is equal to, less than or greater than a given number, the z score formula we use is :

z = (x- μ)/Standard error, where

x is the raw score,

μ is the population mean

n = Random number of samples

Standard error = is the population standard deviation/square root of randy number of samples

= σ /√n

Standard error = σ /√n

σ = 4 mph, n = 64

= 4/√64

= 4/8 = 1/2

= 0.5

z = (x- μ)/Standard error

x = 69.5mph μ = 70mph ,Standard error = 0.5

z = 70 - 69.5/0.5

z = 1

Using the z score table for find the probability,

P(x = 70) = P(z = 1)

= 0.84134

Therefore, the probability that the mean is 70mph = 0.84134

hello from mrbilldoesmath!

answer:

(7 x + 6 y) (49 x^2 - 42 x y + 36 y^2)

discussion:

the trick is to recognize that 343 = 7^3 and 216 = 6^3 and, in general,

a^3 + b^3 =   (a + b) (a^2 - a b + b^2).

in our case

343x^3+216y^3   =   (7x)^3 + (6y)^3

so take a = 7x and b = 6y in the above equation to get the answer.

you,

mrb

a

step-by-step explanation:

the denominator cannot be the same as one of the factors.

8 denominator times 2 denominator = 16

and 7 numerator time 11 = 77

77/16= 77/16 ( they cannot be further simplified)