1. A

    Statistical inference

  2. B

    SPSS Basic Histogram - how to manipulate given data

    Hi I have never used SPSS before and have had a look around the web before posting this. I have a set of data that contains three variables: 1. The name of a road 2. The length of the road; and 3. The suburb the road ends in. I need to create a histogram to compare the distribution...
  3. M

    fitting with individual errors in data

    I have two sets of data x and y with individual errors dx and dy. I want to plot a linear line through the data of the form y=ax+b that takes into account the individual errors in x and y and translates this to an error in the fitting parameters a and b. Is there any method to do this?
  4. L

    How do I analyse clinical data that has a variable number of measurements per patient

    Thanks in advance for any help you can offer. I'm a PhD student and have just finished recruiting for an observational clinical study. Basically, I have recruited 100 patients and performed imaging of their coronary arteries. The measurements of the coronary arteries (e.g. diameter of vessel...
  5. U

    Distributions for data with a gradient

    Hi guys, Firstly, apologies for the thread title - I couldn't think of a good way of explaining this. With reference to the data above (which is just made up numbers for this example), I was wondering how I would determine the 5th and 95th (or whatever) percentiles at any given value on the...
  6. F

    What is an apprpriate statistical test for this data?

    I have 20 subjects, split into 2 unequal groups (Group A has 5 and group B has 15) – the grouping is the independent variable and is categorical/nominal. Every day for 7 days (another independent variable?) I assigned each subject an ordinal score (0 to 7 in steps of 0.5) for an activity...
  7. C

    Help with writing a model formula to fit data?

    Hi, This my first post here so a quick hello to you all :-) I've been struggling with trying to write a formula to fit a set of data that describes a curve and wondering if anyone can help either suggest some formulae to try or a method of going about determing a mathematical model to recreate...
  8. rebirth61213

    Finding the class-widths for a histogram from cumulative frequency data.

    Hi Apologies if this image is of poor quality: it's merely a cumulative frequency graph with time on the x-axis and cumulative frequency on the y-axis. In order to plot a histogram, I need to create a frequency table; it states in the question that there needs to be 6 class widths that are to...
  9. D

    Capture the Inherent Variance in time series data

    Hi All, I was a bit curious to know that Is it possible to capture the inherent variance in the time series data. How can we decide what would be a good MAPE for a particular set of timeseries data. Thank Dinesh
  10. A

    Data Forecasting (Wind Speed)

    Hi, I am engineer, therefore, know very little about the typical terminologies of stat and forecasting. Anyway, I tried to explain my prob. in simple word. I want to generate/forecast wind speed values. The data, I have are: I) Mean II) Max. and Min. differences from mean for the whole period...
  11. S

    Aggregated data analysis

    Hi, I would like to know how it would be possible to make a t-test with aggregated data on SPSS or R. My dataset looks like this: Region......Question.....%positive.......%negative......n 1..............15...............20...................45............2956...
  12. M

    Fitting a data set to an equation to get constants

    Hi, I have a data set with y and x. I have an equation that I want to fit this data to y=a/b(1-e^bx). Can someone tell me how do I plot the data to this equation to get the constants a and b. For a better explanation: Generally when we are given x and y, we can plot this data and use either...
  13. A

    skewed data and kurtosis

    Hi; Anyone know of a good book and/or website on skew and kurtosis (particularly on the bell curve). Thanks.
  14. R

    Given four different data sets, a student calculates the quadratic regression as well

    Given four different data sets, a student calculates the quadratic regression as well as the R^2 value for each using a TI-83. Which of these result models its respective data the best? Set A: a = 1.23 b = -3.27 c = 7.83 R^2 = 0.87394 Set B: a = -3.745 b = 9.524 c = 12.105...
  15. L

    non-linear transformation of a data series

    Hello, As the title suggests, I have a data series and I am looking for an algebraic equation that will allow me to test multiple non-linear transformations of the data. The data is an input metric that is part of a model I am building. I suspect that the metric is not well formed in that the...
  16. O

    Data point falling within 3 standard deviations of mean = Significance?

    Hi all :) Unfortunately, I'm not a math/stats major but a Chemistry major working on my laboratory reports. I do have a data point/result that lies within 2-3 standard deviations from the mean/expected result. What can I conclude from this? I read that 99.7% of the points fall within 3 SD...
  17. R

    When computing the SSE for a given set of data and an equation of the line, the line

    When computing the SSE for a given set of data and an equation of the line, the line of best fit will be A. The equation with the smallest SSE value B. The equation with the largest SSE value C. It doesn't matter if the SSE is large or small D. None of the above Please explain. Thank you!
  18. T

    Homework question regarding data into regression model chart? Please help!

    This is a tough question and I'm just looking for help in it. The questions reads: There are two large data files from different but partnering systems (example: United Airlines & Delta) and asked to create one data file that can be used to create a regression model for analysis. What steps...
  19. I

    Gradient of 2 timeseries data points

    Hi, I'm trying to calculate the gradient of 2 time series data points using the following formula: Arc^-1( Y2 - Y1 ) / (( Time2 - Time1) * (180/PI)) However, I'm getting some strange results. Instead of values such as 30 degress or 20 degrees, I'm getting 0.010 or 0.008 depending of the...
  20. I

    How to use Likert Scale data in regression analysis?

    My knowledge about statistics is elementary and I would really appreciate some help or suggestions in solving my current problem. I am doing a dissertation and I will collect the data using a likert scale. My question is can I use that likert scale data to run a regression analysis to find out...