Answer:
Mean = 78.2
Standard deviation = 5.8
Step-by-step explanation:
Mathematically z-score;
= (x-mean)/SD
From the question;
12% of test scores were above 85
Thus;
P( x > 85) = 12%
P(x > 85) = 0.12
Now let’s get the z-score that has a probability of 0.12
This can be obtained from the standard normal distribution table and it is = 1.175
Thus;
1.175 = (85 - mean)/SD
let’s call the mean a and the SD b
1.175 = (85-a)/b
1.175b = 85 - a
a = 85 - 1.175b ••••••••(i)
Secondly 8% of scores were below 70
Let’s find the z-score corresponding to this proportion;
We use the standard normal distribution table as usual;
P( x < 70) = 0.08
z-score = -1.405
Thus;
-1.405 =( 70-a)/b
-1.405b = 70-a
a = 70 + 1.405b ••••••(ii)
Equate the two a
70 + 1.405b = 85 - 1.175b
85 -70 = 1.405b + 1.175b
15 = 2.58b
b = 15/2.58
b = 5.81
a = 70 + 1.405b
a = 70 + 1.405(5.81)
a = 78.16
So mean = 78.2 and Standard deviation is 5.8
Answer:
698 fishes
Step-by-step explanation:
Generally, we can represent an exponential growth function as;
y = a•(1 + r)^t
originally, there were 3 fishes
The original value in this case means a = 3
After 6 weeks, there were 31
31 in this case is y
r is the increase percentage or rate
t is the time
So, we have it that;
31 = 3•(1 + r)^6
31/3 = (1 + r)^6
10.33 = (1 + r)^6
ln 10.33 = 6 ln (1 + r)
ln 10.33/6 = ln (1 + r)
e^0.3892 = (1 + r)
1 + r = 1.476
r = 1.476-1
r = 0.476 or 47.6%
So the growth percentage or rate is 47.6%
For 14 weeks, we simply have the value of t as 14;
So ;
y = 3•(1 + 0.476)^14
y = 3(1.476)^14
y = 698 fishes
Gradient of line,m=(17-6)/(20-0)=11/20
finding equation of line using a point (20,17)
y-17=11/20(x-20)
y-17=(11/20x)-11
y=11/20x+(17-11)
y=(11/20)*x+6
The figure is rotated 90 degrees counterclockwise around the origin and then translated to the right 6 units.
Answer:
1
Step-by-step explanation:
we have the probability of dyng = 1.3
we have probability of ying =
p0 = p1 = p2 = p3 = 1/3
d = dying
we cross multiply from here
3d = 1+d+d2
3d-d = 1+d2
2d = 1 + d2
(d-1)2 = 0
2d - 2 = 0
2d = 2
divide through by 2
d = 1
therefore there is a a confirmed probability that the ameba from a single cell is eventually going to die out.
