What sample size is sufficient in a qualitative research?

Do the number of FGD participants form part of sample size in any way? use of the number in FGD

25 July 2015 739 8 View

How do I get the approximation of a falling factorial?

I found an approximation in falling factorial. It says that: (a)n-1=a(a-1)(a-2)...(a-n+2) approximate to [a-(n-2)/2]n-1. Can someone tell me how to derive the approximation?

28 December 2014 8,701 3 View

How do I construct a joint pdf for a uniformly distributed sample that is drawn without replacement?

I have a sample X1, X2,..., Xn that drawn from uniformly distributed population. The sample drawn without replacement. Since it depends each other (which is not i.i.d), the joint pdf is not the...

24 November 2014 9,373 3 View

How do I prove that a statistic is appropriate to estimate a parameter?

08 September 2014 6,980 3 View

Did any urologists have experienced with retroperitonel leiomyosarcoma from renal vein with IVC enxtension?

Recently, we got one lady with right side retroperitoneal mass involving renal vein and extends into IVC upto diaphragm. CT suggested leiomyosarcoma. Right kidney separately seen from mass and it...

19 February 2021 6,873 1 View

Wave velocity and rock density paradox?

Practically it is known that seismic velocity increases as rock density increases, why then does the wave velocity equation involving elastic moduli and density indicate that velocity is inversely...

09 February 2021 1,843 3 View

[Covid-19] GGO Evaluation - CT imaging of the lungs ?

13 January 2021 3,115 4 View

Where can I find a dataset for kidney stones images (CT or ultrasound)?

I want to apply neural network on kidney stones images (whether its CT images or ultrasound) to determine whether the kidney has stones or not.

02 January 2021 9,938 3 View

How can the moment tensor inversion results can present good waveform fit (synthetic and observed waveform) from generalized Cut and Paste scheme?

Depending upon the distance of the seismic station from the epicentre, the quality of waveform data and the improvisation of the synthetic waveform on it is often a question. If the Pnl waveform...

31 December 2020 6,602 2 View

How to solve a finite difference equation with both time and space derrivatives?

23 December 2020 2,764 3 View

What is New Next Generation Attenuation Relationships (NNGAR) and how are they different from other attenuation relationships?

Dear researchers The provisions of ASCE 7-10 states that New Next Generation Attenuation Relationships (NNGAR) has been used in the process of Probabilistic Seismic Hazard Analysis (PSHA) to...

15 November 2020 1,132 4 View

How to solve a non linear system?

Hi everybody, I have a non linear system of 9 equations: F=A(F)F+B(F)g(F) F is a 9x1 vector of the unknowns, A(F) and B(F) are 9x9 matrixes which depend on F ang g(F) is a 9x1 vector which...

12 November 2020 9,972 6 View

How i can extract the dose delivered to each pixel of CT image of TPS?

I generated a treatment plane for a patient using intensity modulated radiation therapy (IMRT). I intend to calculate cell survival in each voxel of target volume using LQ model. So, i need to...

03 November 2020 6,132 3 View

Petrel- well coordinates issue?

Hi, After loading 2D seismic lines in Petrel, I added three exploratory wells ( which supposed to be within the same 2D area) but these wells appears off the interesting area when I visualized...

25 October 2020 8,272 4 View