investigation 1

How is our experiment valid

The independent variable has been isolated: variables such as the increments at which HR is measured, waiting for the BPM to return to normal before each trial and cold temp of water to measure it effect on hr. It is only moderately valid because biological differences were not accounted for and the sample size was only one participant

What could be done to improve the validity

• Water circulation: to reduce heat build-up on the hand so that the pain stimulus if more effective.

• Number of participants: only one participant, reducing the generalisation of the experiment, so increasing randomisation decreases sample bias

• Controlling the water temperature: ensure the water is cold enough that it invokes a strong response

• candidate was not fully relaxed, a quiet environment will ensure a better control of variables

• HAVING A CONTROL GROUP (same procedure, except, the water is at room temp) to compare results to ensure the iv is manipulated

what could be done to improve reliability

repeat the investigation multiple times, fix random errors such as natural variation in hr. repetiton reduces influence of random err, as it brings the avg closer to true values. improving validity also improves reliabilty.

how reliable is our experiment

consistently/ moderately reliable as the trial was repeated 3 times and the same procedure followed each time. the results for each time leaned toward the same trend as well.

how accurate was our experiment

moderatley accurate, as a thermometer was used to control temp and a stopwatch used to control time increments, how ever, there was a great degree of human error(incorrect pulse counting) and possibly systematic error (uncalibrated thermometer)

What could be done to improve Accuracy

calibrate thermometer to ensure correct temp is shown, use a calibrated BP/HR monitor for precision and reduce human error. increase validity. also, taking measurements over a longer period of time would give a more comprehensive outlook on the relationship between IV/DV

What is systematic errors were present

incorrect calibration of thermometer

what random errors were present

fluctualtion of water temp, fluctuation of HR

how to improve the errors present?

repeat multiple times (random), calibrate, use more sensitive instruments (systematic) use instruments which can replace human judgement for measurements ( human error)

Draw a conclusion from the data and tables you obtained

From the data obtained, the hypothesis was not supported, as although there was an initial decrease of HR, the final 3 increments prolonged pain exposure. had an increase in HR. The data relates to the aim of this investigation, as exposure to the pain stimulus had a significant effect on hr. Further research is required to understand why there is an initial decrease in hr.

were the results different from those expected?

yes, as the hr decrease fro majority of the experiement

how do the results fit into the braoder context?

initial exposure to a cold stimuli leader to a decrease in HR possibly due to cutaneous vasoconstriction, in which the initial thermoregulatory response to cold exposure and can be elicited through either whole body or localized skin cooling, by reducing blood flow to reduce heat. this facilitated through the SNS. However, prolonged exposure results in a painful stimuli, which activiates the flight or figh resposne, and the SNS increases blood flow to skeletal muscles for effectors to initiate reflexes.The body responds by initiating the fight-or-flight response, mediated by the sympathetic nervous system, releasing stress hormones like adrenaline (epinephrine). This results in increased heart rate.

limitations:

sample size: lack of randomised subjects for generalisation, reduce random errors, external stimuli like room temp or mental stress is not accounted (could impact hr)

bias:

sampling bias: not representative of populations, meausrement biaS: human errors