calcium: Calcium Uptake Data

In SMPracticals: Practicals for Use with Davison (2003) Statistical Models

Description

These are data on the uptake of calcium by cells suspended in a radioactive solution, as a function of time.

Usage

data(calcium)

Format

A data frame with 27 observations on the following 2 variables.

time

The time (in minutes) that the cells were suspended in the solution

cal

The amount of calcium uptake (nmoles/mg)

Details

Howard Grimes from the Botany Department, North Carolina State University, conducted an experiment for biochemical analysis of intracellular storage and transport of calcium across plasma membrane. Cells were suspended in a solution of radioactive calcium for a certain length of time and then the amount of radioactive calcium that was absorbed by the cells was measured. The experiment was repeated independently with 9 different times of suspension each replicated 3 times.

Source

Rawlings, J.O. (1988) Applied Regression Analysis. Wadsworth and Brooks/Cole Statistics/Probability Series.

References

Davison, A. C. (2003) Statistical Models. Cambridge University Press. Page 469.

Examples

data(calcium)
summary(nls(cal~beta0*(1-exp(-time/beta1)),data=calcium,start=list(beta0=5,beta1=5)))

Example output

Loading required package: ellipse

Attaching package: 'ellipse'

The following object is masked from 'package:graphics':

    pairs


Formula: cal ~ beta0 * (1 - exp(-time/beta1))

Parameters:
      Estimate Std. Error t value Pr(>|t|)    
beta0   4.3094     0.3029  14.226 1.73e-13 ***
beta1   4.7967     0.9047   5.302 1.71e-05 ***
---
Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1

Residual standard error: 0.5464 on 25 degrees of freedom

Number of iterations to convergence: 3 
Achieved convergence tolerance: 9.438e-07

SMPracticals documentation built on May 2, 2019, 11:12 a.m.