Why should I choose AnalystNotes?
AnalystNotes specializes in helping candidates pass. Period.
Basic Question 10 of 11
The trees at CW Farms have heights that are normally distributed with a mean of 24 inches and a standard deviation of 2 inches. For a shipment of 25 trees (considered a random sample), what is the probability the average height for the shipment is less than 22 inches?
B. 0+
C. 15.87%
A. 0.1%
B. 0+
C. 15.87%
User Contributed Comments 8
| User | Comment |
|---|---|
| chenyx | The standard error of the mean equal population standard deviation(2) divide by squear root of sample size(25).i.e.standard error=0.4. Under the sampling distribution(distribution of sampling means),the mean equal to the population mean(24), So: z-value=(22-24)/0.4=-5, it means that the probabiliti the 25-trees shipment has an average height of less than 22 is nearly 0. |
| chenyx | In contrast, the probabilities one tree has height of less than 22 is 15.87%.because the z-value=(22-24)/2=-1. |
| NikolaZ | How would you know whether this is a question that is a sampling distribution or just a sample (i.e. whether you would use the standard deviation when trying to find the z-score OR use the standard error?) ?? |
| sgossett86 | My guess is that they're specifically referring to a sample taken from a population for which they have established perameters. THey're not asking you to obtain statistics on the population. The population data is known. |
| Yrazzaq88 | Finally got this right... |
| kaichan91 | If I'm reading this correctly, you use standard error for when you are testing a sample *statistic* as opposed to sample observations. Correct me if I'm wrong... |
| maryprz14 | kaichan91; to answer your question I just copy and paste from the notes; "the STANDARD ERROR of a statistic is the STANDARD DEVIATION of the sampling distribution of that statistic." analyst notes has done an amazing job to explain this. when you take a sample from the population you should calculate the Standard error of the sample and use that as your Standard Deviation (for the sample). I hope I did not confuse you. |
| maryprz14 | and remember statistic vs parameter. |
Your review questions and global ranking system were so helpful.
Lina
Learning Outcome Statements
explain the central limit theorem and its importance for the distribution and standard error of the sample mean
CFA® 2024 Level I Curriculum, Volume 1, Module 7.