Author

Crystal X

@tracyrenee61

articles: 27
total claps: 443
top claps: 124
avg read: 8.3 min
active: 2021-11-03 → 2026-08-06

Wiki topics

📐 · Mathematics · 15 💻 · Programming · 12 🔬 · Science · General · 7 OPS · LLMOps & Inference · 3 GEN · Genomics & Sequencing · 2 💑 · Relationships · 2 EDU · Education & Learning · 2 ML · Machine Learning · 2

Top tags

#statistics ·14 #python ·5 #hypothesis-test ·5 #foster-wheeler ·5 #python-programming ·5 #r-programming ·4 #excel ·3 #wood-group ·3 #classifier ·3 #continuous-distribution ·2

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CR Crystal X

What is the relationship between the null hypothesis and the alternate hypothesis?

I have been studying statistics for a few years now, and one vital part of the science of statistics is the hypothesis test.

Dec 11, 2025 · 2 min read · 124 claps #statistics #null-hypotheses #alternate-hypothesis

What is the relationship between the null hypothesis and the alternate hypothesis?

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A review of the 25 most popular distributions in statistics using Python

One subject that I never studied in my undergraduate and graduate days is statistics. I therefore have had to catch up on the education…

Sep 14, 2024 · 17 min read · 100 claps #statistics #discrete-distributions #continuous-distribution

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Explore statistics with R: Descriptive statistics

Descriptive statistics is a branch of statistics that focuses on summarizing and describing the main features of a dataset. It provides…

Jun 09, 2026 · 4 min read · 67 claps #r-programming #statistics #descriptive-statistics

Explore statistics with R: Descriptive statistics

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Explore statistics with R: Inferential statistics

Inferential statistics is a branch of statistics that focuses on making predictions or inferences about a population based on a sample of…

Jun 10, 2026 · 29 min read · 50 claps #r-programming #statistics #inferential-statistics

Explore statistics with R: Inferential statistics

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Statistics interview question: How do percentiles and quartiles differ?

If you are studying statistics, you will need to know the the measures of dispersion, which include:-

Oct 22, 2024 · 2 min read · 34 claps #statistics #excel #quartile

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Create a simple AI Agent in Excel VBA

In my two previous blog posts I discussed how to create a simple AI agent in both Python and R. these blog posts can be read here:-

Dec 22, 2025 · 2 min read · 25 claps #excelvba #ai-agent

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Use CatboostClassifier to predict on customer churn

Customer churn, or customer attrition, refers to the rate at which customers stop doing business with a company or switch to a competitor.

Mar 03, 2026 · 4 min read · 10 claps #python-programming #catboost #classifier

Use CatboostClassifier to predict on customer churn

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A foray into the functions that apply to continuous distributions

I have been studying statistics for a few years now and one thing that I have discovered is that whenever I learn one concept, I realise…

Jan 10, 2025 · 6 min read · 6 claps #statistics #continuous-distribution #probability-density

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Learn statistics with Python: Distributions used in hypothesis testing

Hypothesis testing is a fundamental aspect of inferential statistics, enabling researchers to make inferences about population parameters…

Aug 07, 2025 · 4 min read · 6 claps #statistics #distribution #hypothesis-test

Learn statistics with Python: Distributions used in hypothesis testing

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CR Crystal X

Statistical interview question: Explain the rate of convergence as it relates to statistics

The central limit theorem (CLT) states that a population with mean (mu) and standard deviation (sigma) and taking samples of the population…

Jul 22, 2025 · 3 min read · 4 claps #python-programming #statistics #convergence

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What is the difference between the ARIMA and the Holt Winters forecasting model?

In the past several blog posts I have covered time series analysis and then time series forecasting on R’s inbuilt datasets. Two main…

Nov 24, 2025 · 2 min read · 4 claps #time-series-forecasting #holt-winters #arima

What is the difference between the ARIMA and the Holt Winters forecasting model?

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Use Python to perform a difference in means hypothesis test

I have been studying hypothesis tests for a while now, endeavouring to expand my level of expertise in this area. One type of hypothesis…

Feb 05, 2025 · 3 min read · 3 claps #statistics #difference-in-means-test #python

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Statistics interview question: What are the three allowed signs in the null hypothesis?

In the field of statistics, the null hypothesis (H0) is the default statistical assumption that there is no significant effect, difference…

Jan 26, 2026 · 2 min read · 3 claps #statistics #null-hypotheses #python-programming

Statistics interview question: What are the three allowed signs in the null hypothesis?

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Explore statistics with R: A/B testing, experimental design, and ethics

A/B testing, also known as split testing, is a statistical method used to compare two versions of a variable to determine which one…

Jun 17, 2026 · 16 min read · 2 claps #r-programming #ab-testing #experimental-design

Explore statistics with R: A/B testing, experimental design, and ethics

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Predict on the probability a Formula 1 driver will pit on the next lap

Formula 1 (F1) is the highest class of international single starter auto racing, featuring purpose built open wheel cars competing in a…

May 06, 2026 · 3 min read · 2 claps #kaggle #catboost #machine-learning

Predict on the probability a Formula 1 driver will pit on the next lap

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My Iranian Boyfriend

I met Mo around 2009. When I worked at Foster Wheeler. I met him on bus number 9. Which was the bus that? Both of us took to work.

Dec 16, 2025 · 13 min read · 1 claps #foster-wheeler #iran #ganstalking

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Article Review: Plan to replace office complex on outskirts of Reading

This morning I was shocked to look at the news on my phone and see that Shire Hall, the former address of my old employer, Foster Wheeler…

Aug 28, 2024 · 3 min read · 1 claps #foster-wheeler #shinfield-park #shire-hall

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Find the z-score using Python

A z-score is a numerical measurement that describes a value’s relationship to the mean of a group of values. The z-score is measured in…

Apr 29, 2022 · 2 min read · 1 claps #python-programming #statistics #z-score

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The Fall of Foster Wheeler: A Tale of Engineering and Ambition

Table of Contents

Feb 28, 2025 · 78 min read · 0 claps #foster-wheeler #amec-foster-wheeler #wood-group

The Fall of Foster Wheeler: A Tale of Engineering and Ambition

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The Fall of Wood: A Sequel

In February I wrote the piece, The Fall of Foster Wheeler: A Tale of Engineering and Ambition, and that post can be read here…

Sep 06, 2025 · 12 min read · 0 claps #sidara #wood-group #foster-wheeler

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Create a normal distribution and test it with Python in Excel

When programming Python in a Jupyter Notebook or other interpreter, the code takes a top-down appearance. The difference with programming…

Oct 16, 2024 · 5 min read · 0 claps #python #excel #statistics

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Use Catboostclassifier() to predict on smartphone addiction

I obtained my first smart phone because I wanted to speak to someone who I had been friends with in the 1990’s whilst serving in the United…

Aug 06, 2026 · 4 min read · 0 claps #kaggle #machine-learning #classifier

Use Catboostclassifier() to predict on smartphone addiction

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Create a gamma distribution and test it using using Python in Excel

In my last blog post, I discussed how to create a beta distribution using Python in Excel and then carry out hypothesis tests on it, and…

Oct 20, 2024 · 3 min read · 0 claps #statistics #excel #python

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Use R’s SARIMA model to forecast quarterly earnings per share

In my last blog post I carried out an ARIMA on the R’s inbuilt JohnsonJohnson dataset, and that post can be read here…

Nov 23, 2025 · 2 min read · 0 claps #r-programming #time-series-forecasting #sarima

Use R’s SARIMA model to forecast quarterly earnings per share

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Musings of an Affiliate Coordinator

From 2006 until 2014 I worked for a major player in the oil and gas industry, Foster Wheeler. My job title was Affiliate Coordinator and I…

Nov 03, 2021 · 2 min read · 0 claps #risk-management #foster-wheeler #amec