1. S

    Essay Question

    Hello all, I have to write an essay at the moment and unfortunately I am stuck on a question, maybe you can help me with it. The question is as follows: "Describe in your own words how an approximation method that determines a confidence interval for the mean of a population from a sample can...
  2. H

    find central tendency

    The following table presents frequency distribution of teachers of 1 year: Rank Frequency Professor 32511 Assoc Professor 28570 Asst Professor 59277 Instructor 14289 Others 3276 1)find mean, median and mode. 2)which is...
  3. N

    mean rank to mean + sd ?

    Hi everyone, We are students trying meta-analysis for the first time using revman software (of cochrane). For one of our study we are stuck because we only have the mean rank and we don't know how to convert the mean rank into mean and standard deviation to obtain our forest plot. If someone...
  4. T

    Computing Mean and Confidence Interval for an Unbalance Dataset

    Hello everyone, I am working on a project in which I am comparing a specific physiological value for a large set of species (75 Species in Total). One of the things that I wanted to do was to compute the mean and confidence interval of the data of all the species together, to show all the data...
  5. L

    Mean and Variance of estimators

  6. B

    Probability Distribution of Cars Sold

    Hi, I'm struggling with where to go with the following problem: The probability distribution below is representative of x, the number of cars sold within a single day. x = 0, 1, 2, 3, 4 P(x) = 0.1, 0.4, 0.3, 0.2 I calculated the standard deviation and mean, which I believe 0.917 and 1.6...
  7. U

    Hypothesis testing for 2 sample proportion

    Previously, the manager measured that the machine effectiveness was at 67.3% with a sample of size of 9. The team has made some improvements by reducing the time of changeovers, major stops and speed loss. Since those improvements, the manager has measured a rate of effectiveness at 78.2% with a...
  8. J

    If mean is between two values, generate response?

    Hi, I am new to Stata and was wondering if it has a way to do something. I have tried researching a lot and can't find anything but im not sure if that's because I'm explaining it badly. I have data where people take a depression test and in the data they all have a score for this test. I want...
  9. S

    Comparing average of two results!

    So here is a question which asks me to compare the mean results. So I calculated the mean number of deaths per 100000 people i.e (2479/216,565,318)*100000 = 1.14. So what to say? The per-day deaths of 2019 were greater than that of in 2020. That's it?
  10. A

    Can I exclude outliers when calculating mean or standard deviation (small-sample)?

    Hey, I am analyzing my results for a high-school biology paper. My data set consists of 20 groups in total, each having 4 repeats, so each is a small sample. I have a few (4) outliers that have a value lower than the control group (which is practically impossible and thus certainly the effect of...
  11. S

    Finding sample mean for normal distribution

    Hello friends, I require help on the below question on normal distribution. "An e-commerce company tries to settle the customer complaints on refund within 5 days. If a refund is not processed within 5 days, then the company has to provide coupons for Rs.500 to the customer. If the company...
  12. R

    Ordinal Model: Acceptability/alternatives to using mean and weighting factors

    I've been asked to validate a model created by someone else and need some help on how the final score is calculated. Have put lots of detail; apologies for the post length. The output (dependent) variable is ordinal scale with 5 points (i.e. 1-5) representing an assessment of risk (not risky...
  13. E

    Overlapping confidence intervals and p values

    Hi, I've been given the mean and 95% confidence interval (CI) of two independent groups and asked if they were satistically significantly different or not? I know that if the CIs of the two groups don't overlap at all, then they can be considered as significantly different. However if the CI do...
  14. D

    Back-calculation (a posteriori) of the minimum sample size for a mechanical experiment

    Hello, I want to back-calculate the minimum sample size for a mechanical experiment. I have a known mean and standard deviation of a statistical population. From the statistical population I chose two samples with means and standard variances I could estimate. My question is: How can I...
  15. J

    Calculation of overall ranking from mean, SD, and Z score

    Hey everyone, I was hoping someone could help me. Im applying for a job, and am trying to work out my overall ranking in two seperate exams so that I can include this in the application. Could someone please tell me if my calculation is correct? I have attached the file with my calculation...
  16. F

    Determining significant difference in mean ratings between two products

    Hi all, I have gathered 180 respondents and asked them to rate two products (so each respondents rates both products). The only difference between the two products is that one product has an extra feature and the other does not. Now I want to know whether there are significant differences...
  17. P

    Which one to choose? Mean or Median

    I have the past two months vehicle arrival time data for a particular vehicle. To find the consistency of arrival time which one should I go for? Mean or Median? Thanks Prashanth.
  18. R

    Normal Distribution of multiple Std.Dev´s and Means

    Is there a way to calculate the Normal Distribution of a set of multiple Standard Deviations (SD) and Means (µ)? I am afraid I do no have Access to the raw data from which the SD´s and µ´s were calculated. Many thanks in advance
  19. A

    Can I compare results from 5 point likert scale to results from 4 point likert scale?

    Can I compare mean (descriptive analysis) from 5 point likert scale to a mean of 4 point likert scale? Results from 5 point likert scale: M: 3.34 (SD: .80) Results from 4 point likert scale: M: 2.18 (SD .44) I want to compare these results, is that possible? Thanks in advance,