2nd one is the answer to it.
What is the question ill try to help
Step-by-step explanation:
In statistics, the empirical rule states that for a normally distributed random variable,
- 68.27% of the data lies within one standard deviation of the mean.
- 95.45% of the data lies within two standard deviations of the mean.
- 99.73% of the data lies within three standard deviations of the mean.
In mathematical notation, as shown in the figure below (for a standard normal distribution), the empirical rule is described as

where the symbol
(the uppercase greek alphabet phi) is the cumulative density function of the normal distribution,
is the mean and
is the standard deviation of the normal distribution defined as
.
According to the empirical rule stated above, the interval that contains the prices of 99.7% of college textbooks for a normal distribution
,

Therefore, the price of 99.7% of college textbooks falls inclusively between $77 and $149.
Answer:
Step-by-step explanation:Knowing that
There are 26 black cards and 26 red ones. Face card consists of jack (J), queen (Q), king (K). There are (26-6)=20 non face red cards. “Either ... or ...” here means bundle of both kinds of cards.
So, there are (26+20)=46 expected cards.
If you also ask for the probability, so the probability of the question asking above is equal to
23/26