# math

posted by .

The population mean length of a hospital stay for surgery is 5.5 days and the standard deviation is 1.9 days. What percentage of patients are hospitalized for 3.9 days or less?

I've read the book and looked at the explanation that it gives and it's not making any sense.

• math -

3.9 days is 2.05 std from the mean.
Look that up in your Z table.
Just use the left tail value.

• math -

What does that mean? What's a Z table and what does std mean?

• math -

## Similar Questions

1. ### Statistics

Upon examining its records, a hospital computes the distribution of the number of days a patient stays at the hospital. They find that 50% of patients stayed just one day before leaving. 30% stayed two days, and 10% stayed 3 days. …
2. ### STATISTICS

Length of Hospital Stays: The average length of “short” hospital stays for men is slightly longer thatn that for women: 5.2 days vs. 4.5 days. A random sample of recent hospital stays for both men and women revealed the following. …
3. ### statistics

A study involving the economic burden of congestive heart failure found that the lengths of hospital stays for patients had a mean of 7.8 days with a standard deviation of 9.1 days. For random samples of size 40, find the sample mean …
4. ### Statistics

According to a study by the Centers for Disease Control, the national mean hospital stay after childbirth is 2.1 days. Reviewing records at her own hospital, a hospital administrator calculates that the mean hospital stay for a random …
5. ### Statistics

According to a study by the Centers for Disease Control, the national mean hospital stay after childbirth is 2.1 days. Reviewing records at her own hospital, a hospital administrator calculates that the mean hospital stay for a random …
6. ### Statistics

According to a study by the Centers for Disease Control, the national mean hospital stay after childbirth is 2.1 days. Reviewing records at her own hospital, a hospital administrator calculates that the mean hospital stay for a random …
7. ### Statistics

According to a study by the Centers for Disease Control, the national mean hospital stay after childbirth is 2.1 days. Reviewing records at her own hospital, a hospital administrator calculates that the mean hospital stay for a random …
8. ### Statistics

According to a study by the Centers for Disease Control, the national mean hospital stay after childbirth is 2.1 days. Reviewing records at her own hospital, a hospital administrator calculates that the mean hospital stay for a random …
9. ### statistics

The experience of a certain hospital showed the the distribution of length stay of patients is normal with a mean of 11.5 days and a standard deviation of 2 days. a. What percentage of the patients stayed nine days or less?
10. ### English

1. He read the book in 5 days. 2. He read the book after 5 days. 3. He read the book within 5 days ~~~~~~~~~~~~~~~~ What does #1 mean,#2 or #3?

More Similar Questions