Order of operations (from high priority to low priority):
Parentheses
Exponents
Multiplications/Division
Addition/Subtraction
All in left to right.
2 ÷ (5 + 3)⁻¹ ÷ 4
2 ÷ (8)⁻¹ ÷ 4
2 ÷ 1/8 ÷ 4
16 ÷ 4
= 4
2 x 5/ 50 x 18
10 / 900
Divide both by 10
1/90
Answer:
a)
And we can find this probability using the normal standard table or excel and we got:
b)
And we can find this probability using the complement rule and the normal standard table or excel and we got:
Step-by-step explanation:
Previous concepts
Normal distribution, is a "probability distribution that is symmetric about the mean, showing that data near the mean are more frequent in occurrence than data far from the mean".
The Z-score is "a numerical measurement used in statistics of a value's relationship to the mean (average) of a group of values, measured in terms of standard deviations from the mean".
Part a
Let X the random variable that represent the time for the step 1 and Y the time for the step 2, we define the random variable R= X+Y for the total time and the distribution for R assuming independence between X and Y is:
Where
and
We are interested on this probability
And the best way to solve this problem is using the normal standard distribution and the z score given by:
If we apply this formula to our probability we got this:
And we can find this probability using the normal standard table or excel and we got:
Part b
And we can find this probability using the complement rule and the normal standard table or excel and we got:
Answer:
Gradient is change in y over change in x.
gradient = y1-y2 ÷ x1-x2
=7-11 ÷ 3-5
=-4 ÷ -2
=2
Answer:
X= -34
Step-by-step explanation: