In this item, we have the mean incubation period of 23 days and the standard deviation is 22 days. We use z-score to determine the unknown in each of the items.
(a) less than 21 days.
z-score = (23 - 21) / 22 = 1/11
This translates to a percentage of 53.6%
(b) z-score for 19 days.
z-score = (23 - 19) / 22 = 2/11
This translates to a percentage of 57.2%.
z-score for 23 days.
z-score = (23 - 23)/ 22 = 0
This translates to a percentage of 50%.
The difference between the two numbers is only 7.2%
(c) z-score of 25.
z-score = (23 - 25)/ 22 = -1/11
This translates to a percentage of 42.3%.
Then, subtract this value from 100 to give us the final answer of 57.2%.
Answer:
-3.16049382716
Step-by-step explanation:
-3/4 = -0.75
-0.75 ^ -4 = -3.16049382716
Answer:
(5, 3 ) and (- 
, - 10 )
Step-by-step explanation:
Given the 2 equations
2x - y = 7 → (1)
xy = 15 → (2)
Rearrange (1) expressing y in terms of x , that is
y = 2x - 7 → (3)
Substitute y = 2x - 7 into (2)
x(2x - 7) = 15
2x² - 7x = 15 ( subtract 15 from both sides )
2x² - 7x - 15 = 0 ← in standard form
(x - 5)(2x + 3) = 0 ← in factored form
Equate each factor to zero and solve for x
x - 5 = 0 ⇒ x = 5
2x + 3 = 0 ⇒ 2x = - 3 ⇒ x = -
Substitute these values into (3) for corresponding values of y
x = 5 : y = 2(5) - 7 = 10 - 7 = 3 ⇒ (5, 3 )
x = - : y = 2(- ) - 7 = - 3 - 7 = - 10 ⇒ (- , - 10 )
Answer:
5 × 
Step-by-step explanation:
