a) ok, except how do you reach a base 1/2 a time ?
round off to 298
b) your wording is not clear. Do you want both coins to be heads, or just any head to be showing?
If you want both to be heads ---> prob = 1/4
number of double heads in 105 events
= 105/4 = appr 26 times
if you want a head to be shown, what we don't want is both tails
prob (some head) = 1 - 1/4 = 3/4
number of times this will happen = (3/4)(105) = appr 79 times
c) You are correct
Please check for me:
Solve the questions below and identify them as experimental or theoretical.
a. A baseball player reaches base 35% of the time. How many times can he expect to reach base in 850 at-bats?
Theoretical –
P(reaches base) = X/850
X/850 * .35 = 297.50
b. Jenna flips two pennies 105 times. How many times can she expect the coins to come up heads?
Experimental –
HH,HT,TT,TH
P ( 2 heads) = ¼
¼ * 105 = 105/4 = 25 ¼
P(1 head) = 1/2
½ * 105 = 105/2 = 52 1/2
c. Gil rolls a number cube 78 times. How many times can he expect to roll an odd number greater than 1?
Experimental
P ( 1, 3) = 2/6 = 1/3
1/3 * 78 = 26
4 answers
Why is it 1 - 1/4 for the probability that one of the coins is sometimes heads? there are 4 outcomes and out of the 4 there are only 2 possibilities that the outcome is only heads. (2/4)
a shoebox holds a number of disks of the same size. there are 5 red, 6 white, and 7 blue disks. you pick out a disks, record its color, and return it to the box. if you repeat this process 250 times, how many times can you expect to pick either a red or white disk?
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1 answer