Answer:
i don't know
Step-by-step explanation:
i don't know
Answer:
can you explain yourself more please
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
The result of our calculations about the rate and time are:
<h3>What is rate?</h3>
Rate can be regarded as the given object with respect to time.
falcon flies= 800,000 meters
t= 4 hours
We were given the formula as (d = rt)
d= distance
r = rate
t = time
We can make our calculations as:
part a:
r=d/t
part b:
falcon's rate in meters per hour = 800,000 meters / 4 hours = 200000m/hr
part c:
falcon's rate in kilometers per hour=(200000m/hr *(1/1000)=200km/hr
part d:
km/hr
Learn more about rate at:
brainly.com/question/8728504
#SPJ1
