Answer:
(78, 80)
Step-by-step explanation:
Given a normal distribution :
Mean = 79 seconds
Standard deviation = 0.5 seconds
Using the empirical rule :
95% of her finishing times :
According to the empirical rule, 95% represents 2 standard deviations from the mean that is ± 2 standard deviations from the mean score or value.
Hence ;
The interval will be defined as ;
Mean ± 2(standard deviation)
79 ± 2(0.5)
79 ± 1
(79 - 1) ; (79 + 1)
78 ; 80
498-53=445
445/2=222.5
222.5+53=275.5
so there were 222.5 student tickets sold
to check: 275.5 + 222.5+498
Answer:
the numbers are 31 and 43
Step-by-step explanation:
you you take 74 and -12 then you divide by 2
The probability of guessing 4 right is
.. (5C4)*(1/2)^5 = 5/32
The probability of guessing 5 right is
.. (5C5)*(1/2)^5 = 1/32
So, the probability of guessing 4 or 5 right is
.. (5+1)/32 = 6/32 = 0.1875
12 5/25 as a simplified mixed number would be 12 1/5
