means

  1. S

    Which statistical procedure to use (given standard deviations and means)?

    Can someone please help me with this? Which statistical procedure could I use, and how could I set this up? A company operates four machines during three shifts each day. From production records, the data in the table below were collected. At the .05 level of significance test to determine if...
  2. D

    Mean and Median for testing data distribution

    Hi, I noticed that in the following articles data distribution is tested via checking for >10% difference in mean and median. http://www.sciencedirect.com/science/article/pii/0022175996000130 http://www.sciencedirect.com/science/article/pii/002217599500078O However, when I follow the...
  3. X

    Find correlation when SD and mean are given

    A guy got 88 in his test which has mean score of 64 with SD 8. He missed the second exam in which the meanscore was 45 and SD was 5. He got a prorated marks of 55. The prof used regression to get his second test marks. What was the corelation between 2 exams ? P.S: I would really appreciate...
  4. H

    Data smoothing

    smoothing compararison
  5. L

    Statistics. Determining the mean.

    Hello! Can someone help me please with this exercise? The Kentucky Derby is held the first Saturday in May at Churchill Downs in Louisville, Kentucky. The race track is one and one-quarter miles. The following table shows the winners since 1990, their margin of victory, the winning time, and...
  6. H

    To combine or not to combine standard deviations?

    Hi, I'm testing the effect of 115 Chinese herbs on bacterial biofilms. I have been carrying out my experiment in microtiter plates and measuring the absorbance readings. My test plate consists of bacterial culture + herb (six repeats of each herb) While my background reading plate...
  7. victorxstc

    Contributions to writing code that enable R to analyze the "Descriptive" statistics

    Apparently R does use only the raw data. In some other statistical programs, there is the option to calculate some simple tests, only by inputting the descriptive statistics. I for one think it would be much better if we could enable R to run such tests too. There are not many tests that can...
  8. A

    Summing Confidence Intervals?

    Hello, I have calculated mean concentrations of various environmental chemicals in a population. These chemicals fall into different classes (PCBs, dioxins, etc). There is a 95% CI associated with each mean concentration. I want to sum the mean concentrations for the chemicals in each class...
  9. L

    Likert scale - mean or meadian?

    HI I have some quesitons on Likert scale. I have 9 statements in 1 questionnaire (scale of 1 to 6). My questions are: 1) I want to display teh result in bar chart...so I have to use median , is it? or do i need to use mean? am i right? 2) If i want to compare two groups (girls and...
  10. P

    Transforming two non-normal sets of data for 2 sample t-test?

    Hey all, Ok so I'm trying to compare the means of two sets of data using a 2-sample t-test. Unfortunately, both sets of data are non-normal. It appears box-cox or Johnson transforms will work, but my question is, wouldn't I need to transform both sets of data using the same transform...
  11. S

    Comparing two means

    Comparing two means Hi. I have some trouble comparing two means in SPSS. I am writing a thesis about audit exemption in Norway, and have found 48 000 companies in the population. 11 000 of these are registrated with e - mail, and are used in my sample. To defend this sample I have to...
  12. S

    Comparing two means

    Hi. I have some trouble comparing two means in SPSS. I am writing a thesis about audit exemption in Norway, and have found 48 000 companies in the population. 11 000 of these are registrated with e - mail, and are used in my sample. To defend this sample I have to compare the mean of...
  13. D

    Calculating 95% confidence interval from mean, SD and number of subjects

    Dear All I have been asked to present some information from a series of published articles according to Mean (+/- 95% Confidence Interval). The statistical summaries are generally presented as: Number of subjects (n) Mean (X) Standard deviation of the mean (sd) How do I calculate the...
  14. K

    which method should I use in this case?

    I have a question. I have several (e.g. VAR01, VAR02, VAR03 ) variables. They are measured twice, one with an intervention and one without intervention. I want to test the hypothesis that the greater change in VAR01 (before and after the intervention) will also result in greater changer in...
  15. M

    Is mean significant and not abnormal?

    Hi everyone! I am having some troubles with interpreting the significance of mean. Mean= 0.19609 St. Dev=0.12341 n=141 I get t-statistic of 18.86763( ratio mean/ st. error) I thought that for the mean to be significant and expected (not abnormal) t-stat has to be within the interval...
  16. Z

    help for task in R programming language

    This is my task. I don't know how to solve it in R studio. Please help me!!! Simulate: a) 15 values from N(0,1) distribution b) 50 values from N(1,5) distribution c) 30 values from exp distribution with parametar 2 For all these I hade to find mean, standard deviation, deviation. And...
  17. J

    Interpreting main effects in long. mixed model when interactions w/ time are in model

    I am running a mixed effects longitudinal model with linear and quadratic time effects and a continuous outcome. I have a covariate that has a significant interaction with time-squared, so obviously the linear interaction and its main effect are left in the model. When interactions are in the...
  18. E

    How do I report marginal means of a two-way unrelated ANOVA correctly? APA-style

    Hello, after doing a two-way unrelated ANOVA (General Linear Model > Univariate) on SPSS, I am confused how to report the output correctly. My professor told me to report only the marginal means of the cell means (I have 4 cells) but how exactly do I do that? Do I subtract one from the...
  19. P

    Comparing mean averages from survey

    Okay, I am fairly new to SPSS but am pressed for time in seeing if any statistically significant differences (.05) are evident. I have two groups (1) (n=30 and (2) n=40). I asked 28 survey questions and have the mean average for each question from each of the two groups. When I try to...